In 1 Corinthians 15:2, it says that we are saved unless we have believed in vain. How does one believe in vain? How can I know that my faith in Christ is strong enough?

This passage says that we would believe in vain if Christ had not really been raised from the dead. There were some among the Corinthians who had been saying that there was no resurrection of the dead. The Holy Spirit through the apostle Paul tells us that if you say that there is no resurrection of the dead, then Christ is not risen, our preaching is in vain, our faith is in vain, and we are still in our sins (1 Corinthians 15:12-19).

However, we read in verse 20, "But now is Christ risen from the dead." In fact, after His resurrection He was seen by about five hundred brethren at one time. So no one can really believe in vain because Christ has risen from the dead. Paul is led to put it that way to show what would be true if Christ were not risen. How we can thank God for a risen Saviour!

We can also thank God that our eternal salvation is not based upon the strength or weakness of our faith. If that were so, none of us could be saved. No, our faith, whether strong or weak, is in the Lord Jesus who by His death upon Calvary's cross has satisfied every claim that God could have against us. When I put my faith in a certain airline to take me to my destination, my faith is based upon the airline's reputation. When I put my faith in the Lord Jesus Christ and His finished work upon the cross to take me to heaven, my faith is based upon the character and trustworthiness of God. It's not the amount of faith, but who and what the faith is in that really matters. I may have little or weak faith but it is in a great and strong Saviour and He has promised to keep me and bring me safely home to heaven (John 10:27-30).