I. We sometimes feel a difficulty in understanding why Paul should be so very earnest in insisting on the resurrection of the body. It seems as if he thought that without that element the belief of immortality might not only fail to exercise a good influence, but might even exercise an evil influence over one who so embraces it. The favourite doctrine of the gnostics that matter is in itself essentially and incurably corrupt, and is the cause of all corruption, compelled them to deny the possibility of a literal bodily resurrection. From this theory of theirs two practical conclusions flowed. It led them to throw the entire blame of whatever evil still adhered to them not on the renewed and risen soul, but on that dead and defiled body which would not let the soul purely and freely live. And worse than that, it led them to argue that the amount of evil, more or less, which might still adhere to them, was really very much matter of indifference. Since being all centred in the body, it would all be got rid of when the body was cast aside. Thus by brief stages their error led to sin. Well might the Apostle write the solemn warning, "Be not deceived; evil communications corrupt good manners"!
II. The Apostle is here thinking of that deeper and wider view which he has been taking as to the bearing of the denial of the resurrection on the entire scheme of the gospel as a provision of life and salvation for the lost and guilty children of men. If Christ is not risen bodily, then all proof is wanting of His emancipation, and ours in Him from the penalty of sin. All proof is wanting of His righteous justification for us and our righteous justification in Him.
R. S. Candlish, Life in a Risen Saviour,p. 109.