Why can faith not be a condition of salvation? This question is one of importance today as faith has been made to be that primary condition that saves a man. Faith is said to make one right with God.
Romans 3:20 Therefore by the deeds of the law there shall no flesh be justified in his sight: for by the law is the knowledge of sin.
Paul very specifically tells us that by the deeds of the law shall no flesh be justified. To be justified is as Paul describes here. It is in the eyes of God to be seen as holy and just and good. It is to appear in the eyes of God as righteous. By the deeds of the law shall no flesh appear righteous. Look at the words of Jesus in Matthew 23:
Matthew 23:23 Woe unto you, scribes and Pharisees, hypocrites! for ye pay tithe of mint and anise and cummin, and have omitted the weightier matters of the law, judgment, mercy, and faith: these ought ye to have done, and not to leave the other undone.
Christ points out the hypocrisy of the pharisees stating they follow the minor points of the law. What they did was to not follow the major, or weightier matters of the law. What are the weightier matters of the law? Jesus mentions judgment, mercy, and faith. He says these you ought to have done. Christ Himself tells us these are things that we do. To do something is to perform a work. Jesus specifically tells these men they should have performed the act of faith. There was no specific law that said have faith. What Jesus was pointing out here was faith as well as judgment and mercy were built into the law. Faith was part of the law. To follow all of the law, one would have to perform the act of faith. To fully adhere to the law, one would have to perform the act of faith non-stop and perfectly all throughout ones life. Christ was telling them faith was one of the more important points of the law. Paul in Romans tells us that by the deeds of the law there shall be no flesh justified. Faith cannot be that which leads to our justification. Though we do have faith, it is not to be made right before God. It is not to be seen as righteous. Faith is what we have, it is what we are given by God to see that we are justified in His sight.