What does 1 Corinthians 15:20 mean?

In verses 13–19, Paul followed a premise to its logical conclusions: What if there is no resurrection from the dead? That's what some among the Corinthians were saying. Paul showed that if such a thing were true, it would mean Christ was not raised from the dead. And if Christ was not raised, the gospel is false, the apostles are liars, and believers in Jesus are still unforgiven for their sin and separated from God. The persecution endured by believers is pointless, and our suffering is meaningless (2 Corinthians 11:24–28).

Thankfully, the logic of this situation does not stop there. Christianity is tied, entirely, to the resurrection of Christ. If there are dire consequences for it being false, it stands to reason there are profound reasons to celebrate if it is true.

Here, Paul throws all the "what if" conclusions aside in a grand declaration of what is indeed true: Christ has been raised from the dead (Matthew 28:6)! Even better for those who believe in Him, Christ was not the last to be raised from the dead. Instead, Paul describes Him as the "firstfruits" of those who have died—those who have "fallen asleep".

The firstfruits were the first of the season's crops given by faithful Jewish people to God. Paul's use of the term here means that Jesus was the first of the crop of "the dead" to be resurrected. His was the prototype for what lies in store for believers in the future (1 Corinthians 15:51; 1 John 3:2). In other words, that harvest has only just begun. As God raised Jesus back to life, He will collect all those who trust in Christ to life, as well, when the time comes.