Transformation not only of our souls but also of our bodies is necessary to dwell in God’s presence in the new creation forever. Paul has stressed this point in 1 Corinthians 15:35–49, where we see that possessing a renewed and resurrected body just like the body of Christ is the sure hope of all who are in Christ. The Apostle continues to argue this point in today’s passage, explaining that a transformed physical body is necessary because “flesh and blood cannot inherit the kingdom of God, nor does the perishable inherit the imperishable” (v. 50).
Importantly, Paul is not disparaging physical existence as such. Neither is he teaching that we will shed our bodies in favor of existence as pure spirits once Jesus returns to consummate His kingdom. After all, in His resurrected body, Jesus possesses flesh that can be touched and seen, though it is flesh that has been renewed by the Spirit (see John 20:24–29). Since we will be like Jesus, our resurrected bodies will be physical as well (see 1 Cor. 15:49; 1 John 3:2). But it will be transformed flesh and blood. As John Calvin comments, “Flesh and blood we must understand, according to the condition in which they at present are, for our flesh will be a participant in the glory of God, but it will be—as renewed and quickened by the Spirit of Christ.” Remember that in the present, even our physical bodies have been affected by sin, and they are subject to death and decay. This must change for us to enter the kingdom, for death and decay are incompatible with the Lord who is the living God. Scripture emphasizes this in many ways. For example, many of the old covenant purity laws indicate this incompatibility by pronouncing unclean that which has contact with dead things (see Num. 19:11–22).
So, our physical bodies must be rendered imperishable by the power of God at the resurrection of the dead for us to live with God in eternal blessing forever. This will happen when the trumpet sounds and Jesus returns. All believers will receive glorified bodies on that day, even those who do not die before our Lord comes (1 Cor. 15:51–52). Matthew Henry comments that the trumpet “is the loud summons of all the living and all the dead, to come and appear at the tribunal of Christ. At this summons the graves shall open, the dead saints shall rise incorruptible, and the living saints be changed to the same incorruptible state.”