Why does Paul call Christ the first fruits of those who have died?

Paul calls Christ the first fruits because His resurrection is the first sampling of the coming resurrection harvest. Just as Israel’s harvest began with early ripening heads of grain before the main harvest, Christ risen from the dead anticipates and illustrates the later resurrection of those who have died.

Les explains this by pointing back to Leviticus 19 and the Jewish harvest. There were three aspects: first, the sampling of the early ripening heads of grain; then the main harvest; and finally, the corners and gleanings left for the poor. Les suggests Paul is using that Israeli harvest system as an illustration of the resurrections that are coming. When Paul says Christ has risen from the dead and become the first fruits of those who have died, Les sees it as a clue to understand the resurrection truth Paul is presenting. He also notes that this subject requires qualification and more time than he has in that setting.

1 Corinthians 15

What does Paul say Christ became after rising from the dead?

Paul states that after rising from the dead, Christ became the first fruits of those who have died. This identifies Him as the first fruits, the initial sampling in the harvest pattern that illustrates the coming resurrections, corresponding to Israel's early ripening heads of grain taken before the main harvest.