Sola Fide was one of the main points of the Reformation. The Reformation (to give a short background) began when the protestants split from the Catholic church in a movement lead by Martin Luther, John Calvin, and others. Sola Fide, along with Sola Scriptura (Scripture alone), were statements of the different principles between them and the church. From these stem main points about what we believe.
Faith alone is the principle of salvation by faith. And only faith. In Paul's time (and apparently before), a belief was running through the Jews (and early Christians) that salvation could be attained by works. Paul wrote extensively on this topic, clearly presenting that works are worthless without faith and without a proper heart. This belief, however, is even more prevalent in this time than it was then. Even some people who say they don't believe in salvation by works, they unknowingly do. I feel like Sola Fide is such an important principle that I would write about it in a post.
Paul is clear that works, without faith, are dead. But James sports a seemingly contradictory statement: faith without works is dead. How can both of these things be true? People who say that salvation needs works along with it point out the passages of James. But what if it's like two different sides of a coin? Paul was pointing out that works, without a proper heart (which is what God sees) mean nothing eternally. Salvation can only be attained by faith. James, means that a heart for God will and should have good works. Jesus says He knows believers by their fruits. But if you believe that you can only go to heaven by good works, than you contradict stories in the Bible. For example, when Jesus was on the cross, a thief, being crucified next to him, voiced his faith. Jesus told him that He would see the man in paradise. Had this man done anything? No. His only good work was believing in Christ, since before you have faith your works mean nothing-and even if they had, it didn't seem like he had many to show. Also, many times Jesus told people that their faith made them well, not their works. Also, Paul speaks in Philippians of his perfection when conformed to the law and works-and he counted none of it as gain. How could he count none of it as gain if it had any eternal value?
Now don't get me wrong. Works are good, and should be everywhere in a believer's life. It's when you start relying on them to get you to heaven or to earn favor with God where it becomes a stumbling block. Let's just pretend that for almost all of your life you were pretty much free from sin, and you never stopped doing good works. Let's just pretend that your fruits numbered 100 from this venture. (I know it's unrealistic, but bear with me.) When it comes you judgement day, you have your 100 fruits and you look around and see people with their 2 fruits and their 5 fruits, and even people who only have 1 fruit. But when God comes up, you see that the requirement is 100,000 fruits. Then you realize that you don't have enough, and neither does anyone else. But salvation is a free gift, and that is what bridges the gap of 999, 900 fruits. More than that, even. We cannot rely on our own works. When we rely on our works, our salvation is found in ourselves. But salvation is found in no other name than the name of Jesus! Salvation is found in faith, not works. "Believe in the Lord Jesus Christ, and you will be saved." Not "Believe and do good works, and you will be saved." Works stem from our beliefs, not the other way around.
So we are to rely, not on self, but on God. The Bible clearly speaks that our salvation is is only found in faith. We are supposed to rely on God. Sola Fide. Faith Alone.