Paul knew he had to respond to their concerns. The planting of a seed and the harvesting of a crop will help you understand many areas of the Christian life. Paul adds resurrection to the list of seed-time and harvest teachings. We are a seed. And like a seed, when we are placed in the earth, we will bring a harvest one day.
Resurrection day is harvest time.
Every seed has a shell and a heart. So do God's people. Our body is the shell which surrounds our eternal heart. If we better understand a seed, we can better understand resurrection and our future resurrection body. When the shell of the seed dissolves in the ground, the life is released from the seed's heart.