The Seriousness of Denying of the Resurrection of the Dead

1 Corinthians 15:12-19 (NASB) (12) Now if Christ is preached, that He has been raised from the dead, how do some among you say that there is no resurrection of the dead? (13) But if there is no resurrection of the dead, not even Christ has been raised; (14) and if Christ has not been raised, then our preaching is vain, your faith also is vain. (15) Moreover we are even found to be false witnesses of God, because we testified against God that He raised Christ, whom He did not raise, if in fact the dead are not raised. (16) For if the dead are not raised, not even Christ has been raised; (17) and if Christ has not been raised, your faith is worthless; you are still in your sins.
(18) Then those also who have fallen asleep in Christ have perished. (19) If we have hoped in Christ in this life only, we are of all men most to be pitied.

Verse 12 gives us the reason the Holy Spirit directed the Apostle Paul to write about the resurrection of the dead: “Some among you say that there is no resurrection of the dead.”
If we deny the resurrection of the dead, then there are nine thoughts we must grapple with:

1. We are going against the message of God: “Christ has been raised from the dead,” verse 12.
2. There is no resurrection of the dead, verse 13.
3. Christ has not been raised, verses 13, 14, 15, 16, 17.
4. Our preaching is vain, verse 14.
5. Our faith is vain and worthless, verses 14, 17.
6. We are false witnesses of God because we have testified against God that He raised Christ whom He did not raise, verse 15.
7. We are still in our sins, verse 17.
8. Those who have fallen asleep in Christ have perished, verse 18.
9. We have hoped in Christ in this life only, and we are of all men most to pitied, verse 19.

Anyone who denies the resurrection of dead does not believe in God, Christ, the Holy Spirit, Their power, and the Word of God.  There is no middle ground.  We are either for Christ or against Him.