Let us first consider salvation. What does it mean to be "saved"? Why is it necessary to be "saved" in the first place? Thayer defines the Greek word for salvation, soteria, as, "deliverance, preservation, safety, salvation." This is consistent with Webster's basic definition of the English word: "the act of saving; preservation from destruction, danger or great calamity."
Thus, inherent in the concept of salvation is the need for deliverance. This is something evident no matter what approach we take to understand salvation: salvation as redemption demands that we must have incurred some cost; salvation as deliverance demands that we must be delivered from something; salvation as atonement demands that there is something for which we need atonement.
Put simply, our idea of "salvation" or being "saved by x" must still make sense if we take out "salvation" or "saved" and insert "deliverance/delivered," "rescue/rescued," and the like instead. If it does not make sense, then we have strayed from the God's concept of salvation.
Thus, why do people need salvation? This is when we can start speaking of law. But what is the law, why is there law, why does the law matter, and what is the relationship between law, sin, salvation, and condemnation?
A law is a rule-- a code of conduct. The Ten Commandments in Exodus 20:3-17 represent the quintessential expression of law: you shall honor your father and mother. You shall not bear false witness. Laws express what is to be done versus what is not to be done.
It is true that law exists to provide structure and definition to conduct (Romans 7:7, 1 John 3:4). Before there was sin there was a law of sorts-- Adam and Eve were not to eat of the fruit of the tree of the knowledge of good and evil (Genesis 2:16-17). Nevertheless, the essential reason for law is captured by Paul in Galatians 3:19 and 1 Timothy 1:9: law is there because of those who break them. Yes, God established the universe in justice (Psalm 89:14), but the particular parameters of how justice works in the case of how an Israelite is to handle a Hebrew slave must be set forth because of man's propensity toward rebellion (Exodus 21:1-11).
The Law, as the expression of what is right versus what is wrong, is good, holy, and perfect (Psalm 19:7, Romans 7:12). But what can the Law-- or, indeed, any law-- do? Law does not do anything-- it simply is. Law defines good conduct and bad conduct, what is commendable and what is abhorrent. Based upon law, one can be defined as compliant with the law or in transgression of the law. But what does that really mean?
This is when we must make the necessary separation between law and consequence. For example, if the law states that one is to drive a vehicle no more than 65 miles an hour down a given road, but I am driving 70 miles an hour, I am in violation of the law-- a transgressor. But what happens if those charged with enforcing that law do nothing about it? What if, while I am in transgression, they actually pass me and are going even faster? I might be a transgressor, but there is no consequence. In a similar way, if one is following the law and driving no more than 65 miles an hour, what happens? Nothing. One is in compliance with the law. One may not be afraid of any penalties, but there is no expectation of some reward.
Therefore, by definition, no one can ever be "saved by law," since the Law-- any law-- can do nothing on its own. Law just tells you what is right and what is wrong. By law, one may be defined as compliant or as a transgressor, but such a definition does not automatically lead to some kind of deliverance or condemnation. There must be some other acting agent that provides a consequence-- a reward or a punishment. Law, on its own, can do no such thing. This is why no one in the New Testament ever talks about law in terms of salvation. As we will see, law is spoken of in terms of justification, and there are very good reasons for that.
We can think about this in another way. If we rephrase "saved by law" according to our standard above, it is saying that we are "rescued by law" or "delivered by law." How could such a thing happen? If we have broken the law and stand condemned as transgressors, can the law somehow save us? No-- it is the very thing that has defined us as transgressors! The law, on its own, has no means of redemption or rescue; it just declares things as they are. But if we have not broken the law in any way, shape, or form, then the statement is still meaningless, because what are we being delivered from or rescued from? How can the law deliver us or rescue us if we have not done anything that has caused us to need deliverance or rescue?
Thus, one cannot talk about salvation, or rescue, by law-- law calls balls and strikes, so to speak, and cannot on its own establish consequence. Nevertheless, one might attempt to base his standing before God on the basis of adherence to the law-- the attempt to be justified by the law, or to be declared righteous by law. Yet, as Paul declares, this is impossible:
Because by the works of the law shall no flesh be justified in his sight; for through the law cometh the knowledge of sin (Romans 3:20).
In fact, Paul declares that this has never been possible:
Now that no man is justified by the law before God, is evident: for, "the righteous shall live by faith;" and the law is not of faith; but, "he that doeth them shall live in them" (Galatians 3:11-12).
Paul is quoting Habakkuk 2:4 and Leviticus 18:5, respectively, to show that even under the old covenant-- under the Law-- no one has been justified by their adherence to the law before God. The reason why this is the case is provided by James:
For whosoever shall keep the whole law, and yet stumble in one point, he is become guilty of all. For he that said, "do not commit adultery", said also, "do not kill." Now if thou dost not commit adultery, but killest, thou art become a transgressor of the law (James 2:10-11).
Once one breaks one law, one is a transgressor. It does not matter whether he follows or does not follow the Law for the rest of his life. Everyone in the Old Testament, at some point, broke the law. Abraham lied (Genesis 12:10-20). Moses killed a man, and disobeyed God's command (Exodus 2:12, Numbers 20:10-12). David committed adultery with Bathsheba (2 Samuel 11). In so doing, they all became transgressors. No matter what else they were to do or not do in their lives, they would stand before God as transgressors of the Law. Thus, their standing before God could not be based on their adherence to His law, for they did not completely and fully adhere to that law! That was true then and it remains true now (Romans 3:23)!
All of this is why Paul shows strenuously in Romans 7 that the law is not the problem or the solution. It just is. The problem that demands the solution-- the reason why we need saving in the first place-- is sin. Yes, sin is defined by the law-- the commission of that which the law proscribes, the omission of that which the law prescribes-- and sin is lawlessness, acting outside of the authority of the law, as John says in 1 John 3:4. Yes, without the law, sin lies dead, since it has no definition (Romans 7:8). Sin and the law, then, are quite intertwined, but the law remains holy while sin remains quite unholy and the problem.
Why is sin a problem? If there were no consequence for transgression, then there would be no problem. Nevertheless, from the beginning until now, the consequence of sin-- transgression of the law-- is death (Genesis 2:17, 3:14-19, Romans 6:23). That consequence exists because God has fixed it as existing. God, as the Creator of the universe, has not only defined the law but also has established the consequences of one's obedience or disobedience to the law. Those who transgress the Law are condemned (2 Thessalonians 1:6-9)!
Therefore, since God is the Agent establishing the consequence, whatever rescue/deliverance/salvation that exists will involve Him and be defined by His actions. In order to overcome the challenge of sin and death, He sent His Son Jesus to accomplish what humans and the law could not. Jesus lived the perfect life, not transgressing any law, but fulfilling it (Matthew 5:17-18, Hebrews 4:15). When He was executed, His sacrifice could atone for our misdeeds because He was pure (Hebrews 9). He died, not because of His own sin, but because sin and death were in the world; death could not hold Him, however, because He was not guilty of sin and thus did not incur the consequence of death (Acts 2:24). Thus God established a way to rescue humans: their burden of sin could be forgiven through Jesus' blood, and just as Jesus overcame death in the resurrection, so also could His followers (Romans 5:9-11, 8:17-24). This the Law could never do, as Paul explains:
For the law of the Spirit of life in Christ Jesus made me free from the law of sin and of death. For what the law could not do, in that it was weak through the flesh, God, sending his own Son in the likeness of sinful flesh and for sin, condemned sin in the flesh (Romans 8:2-3).
Thus, God is the One who can save. On their own, humans can do nothing about their sin except stand before God as transgressors deserving condemnation. There can be no justification by law, for law just tells it like it is, and the flesh is weak. On what basis, then, is there justification? On what basis does God declare a person righteous? On what basis does God rescue a person?
We understand that our justification and thus our salvation are through Jesus Christ. I fear, however, that we still look at that justification and salvation in terms of law, only now it is the law of Christ. We confess that our "moral striving"-- our attempts to be good people and do what we should-- before we learned of Christ failed and did not accomplish what we sought. Yet it seems easy to think that now since we have come to know about Jesus, we can now get somewhere with our "moral striving!"
Yet it is really no different. We cannot be justified by law in the new covenant. We can go through the plan of salvation and have our past sins covered through the blood of Christ, but what happens the moment when we sin again? Will anyone who is a Christian declare that they have never transgressed the law of Christ from the moment of their conversion until this very moment? By no means!
This is why Paul says in Romans 3:23 that all have sinned (past tense) and fall short of the glory of God (present tense). We are still not there. We still transgress God's will by doing that which is proscribed and not doing that which is prescribed at times. To say or act to the contrary is self-delusion and folly (1 John 1:8)!
Thus, we are not justified by the law of Christ, because we have all transgressed the law of Christ-- in other terms, if our attempt to stand before God was based on that law, we would be condemned as transgressors. All of our obedience to the law of Christ would be vitiated by our disobedience against it.
Therefore, our confidence cannot be in our obedience, because we have not been fully obedient. Our "moral striving," on its own basis, now counts as much as our "moral striving" did before we learned of Christ.
This is why God stresses through Paul that we are saved-- delivered or rescued-- by grace through faith, and that our justification is based on faith (Galatians 3:24, Ephesians 2:8). Notice what was necessary for our rescue: God loving us even though we were unlovable, willing to suffer the death of His Son, His Son Himself willing to suffer and humble Himself, and so on (cf. John 3:16, Romans 5:6-11, Philippians 2:5-11). We did not deserve this or earn it in any way-- it was given as a gift, and thus is rightly reckoned as grace. Yet grace, on its own, is clearly insufficient, or else everyone would receive deliverance and rescue through Jesus, and God makes it clear that such will not be the case (Matthew 7:13-14, 21-23, Romans 2:5-11, 2 Thessalonians 1:6-9). That is why salvation is by grace through faith-- we must believe that God exists and that He has acted definitively against sin and death through His Son Jesus Christ (Hebrews 11:6, Romans 8:1-3).
But what is this faith? Can it be mere mental assent to the proposition of God acting in Christ? By no means, for demons mentally assent to God's existence and saw the work of Christ, but were not saved (Matthew 8:29, James 2:19)! We must certainly intellectually assent to the existence in God and deliverance in Christ, but faith goes far beyond this.
James makes it evident in James 2:14-26 that faith without works is dead. Whereas faith and obedience are often held in tension by many today, such tension is not coming from the New Testament. Paul can speak in the same letter about justification by faith and that we cannot be justified by works of the law (Romans 3-5) and also speak of the need for obedience and judgment on the basis of works (Romans 1:5, 2:5-11, 6:1-22).
This is because faith, at its core, is confidence and trust. We cannot be saved by our works, since we have done bad things and not done every good thing. The Law cannot help us, since the Law just tells it like it is. God in Christ, however, can deliver us, and has provided the means of deliverance through the life, death, and resurrection of Jesus of Nazareth. Yet we must place our confidence and trust in Jesus as Lord, since He was given all authority (Matthew 28:18) and is the Mediator and High Priest of the new covenant (Hebrews 7-9).
Can we really say that we put our confidence and trust in Jesus if we refuse to follow what He has said and done? Of course not, and that is why anyone who would do such a thing stands condemned according to Matthew 7:21-23. Putting our confidence and trust in Jesus demands that we seek to do what He has said-- to do what He tells us to do, to avoid what He tells us to avoid (1 John 2:3-6).
So yes, ultimately, we must strive to be obedient to God in Christ (Romans 6:16-18). But we cannot put our trust in our obedience or in that law-- we put our trust in God in Christ. We must do this because we do not always uphold the law of Christ. Even though we strive to be obedient, many times we prove to be disobedient. If our trust is in our following of His law, those moments of disobedience stand condemning us. But if our trust is in God in Christ, and we recognize those times when we prove disobedient, and we confess those times before Him and plead to be forgiven, and we continue to seek to be His obedient servants, then God is faithful and righteous to forgive us and maintain our cleansing (1 John 1:9).
This is why we are justified by faith-- it is the only means by which we can follow after God's purposes while receiving forgiveness for our deficiencies and insufficiencies. That is why Paul describes the church as the bride of Christ whom He has cleansed by the washing of water with the word, leading to its sanctification (Ephesians 5:25-27). We cannot be rescued while we remain in our sins and under the penalty of death. Jesus is the means by which we can have forgiveness of sins and thus be released from the penalty of death. Without that cleansing we remain filthy; without the opportunity for continuous cleansing, we will become as defiled as before, and again be subject to the penalty of death. Continuous cleansing cannot come through obedience to the law any more than our original cleansing came through it. It only comes from the gracious favor of God, and God only bestows it upon those who place their trust in Him and His Son and who ask for it (Ephesians 5:25-27, 1 John 1:9)!
Therefore, we are not saved by our works or by our obedience, but we cannot be saved without them. Works and obedience are insufficient, for they are not complete; since they are not complete, confidence in them only leads to condemnation. It is through faith that we receive the blessings of God's grace as manifest in Christ, but that faith itself is insufficient if it does not lead one to strive to be an obedient servant of the Lord Jesus Christ. But there is never a time when that obedience eclipses faith, for we continually fall short of God's glory, and thus cannot be justified by our obedience. We must instead seek to do God's will as reflected in the law of Christ in the New Testament because we understand that God is our Creator and we are the creation, and that He has declared His Son Jesus as our Lord and Savior. Ultimately, everything flows from our faith in Christ: we trust that since He lived a perfect life, that we ought to walk as He walked (1 Corinthians 11:1, 1 John 2:6). We trust that since He is Lord of heaven and earth, we ought to do what He says to do, follow His commandments, and serve Him (Romans 6:16-18, 1 John 2:3-5). We trust that since God loved us enough to send His Son to die for our sins, we ought to avoid sin, but when we fall short, if we humble ourselves, admit our wrongdoing, and seek to do it no more, that He is faithful and righteous to forgive us of those sins (1 John 1:9). Finally, we trust that since He has done what He has said He would do, we can be confident that the day of Judgment will come, God will render to everyone according to what they have done, and those who are declared righteous because of their trust in Jesus will receive eternal life and glory, while all others will receive condemnation and torment (Acts 17:30-31, Romans 2:5-11, 8:17-18, 2 Thessalonians 1:5-12).
God created the universe in justice, establishing His Law as the governing principle of the creation. By transgressing that Law, man has sinned and suffers the consequence of death. All the law can do is declare what is right and wrong; it by itself cannot justify. God has shown mercy in that while we remained in sin and could do nothing about it, Jesus His Son died for the ungodly. We can obtain that mercy by trusting in Him, and that trust demands that we renounce our own ways and seek His ways. Nevertheless, we always stand in need of that mercy, and at no point can trust in our own obedience. Let us always trust in God in Christ, and not in ourselves!