V.1-11 Imaginations, arguments, and false views concerning the resurrection of the body had come in too. Some were denying the resurrection of the dead. Yet the resurrection of Christ was a vital part of this gospel they had heard from Paul and had believed.
V.12-19 If there was no resurrection of the dead, then Christ was not raised, and they had believed for nothing, for they therefore would be yet in their sins.
V.20 Glorious, victorious; taking the sting of death out of every believer’s funeral.
V.21-23 All in Adam’s family die; all in Christ’s family shall be made alive. The resurrection of the lost is not mentioned here.
V.24-28 Christ will eventually give up His kingdom — at the end of the millennium — after all His enemies are put under His feet including death that God — as God, Father, Son and Holy Spirit in One — may be all in all. Verses 20 to 28 are a parenthesis. This helps us to understand the next two verses. Read 17, 18, 19, 29 and 30 all at once.