James 2:24, not by faith alone
The scriptures clearly teach that we are saved (justified) by faith in Christ and what He has done on the cross. This faith alone saves us. However, we cannot stop here without addressing what James says in James 2:24, "You see that a man is justified by works, and not by faith alone."
There is no contradiction. All you need to do is look at the context. James chapter 2 has 26 verses: Verses 1-7 instruct us not to show favoritism. Verses 8-13 are comments on the Law. Verses 14-26 are about the relationship between faith and works.
James begins this section by using the example of someone who says he has faith but has no works, "What use is it, my brethren, if a man says he has faith, but he has no works? Can that faith save him?" (James 2:14). In other words, James is addressing the issue of a dead faith, a faith that is nothing more than a verbal pronouncement, a public confession of the mind, and is not heart-felt. It is empty of life and action. He begins with the negative and demonstrates what an empty faith is (verses 15-17, words without actions). Then he shows that type of faith isn't any different from the faith of demons (verse 19). Finally, he gives examples of living faith that has words followed by actions. Works follow true faith and demonstrate that faith to our fellow man, but not to God. James writes of Abraham and Rahab as examples of people who demonstrated their faith by their deeds.
In brief, James is examining two kinds of faith: one that leads to godly works and one that does not. One is true, and the other is false. One is dead, the other alive; hence, "Faith without works is dead," (James 2:20). But, he is not contradicting the verses above that say salvation/justification is by faith alone.