Thematic Bible: Why the body dies

But if Christ lives in you, [then although] your [natural] body is dead by reason of sin and guilt, the spirit is alive because of [the] righteousness [that He imputes to you]. And if the Spirit of Him Who raised up Jesus from the dead dwells in you, [then] He Who raised up Christ Jesus from the dead will also restore to life your mortal (short-lived, perishable) bodies through His Spirit Who dwells in you.

But someone will say, How can the dead be raised? With what [kind of] body will they come forth? You foolish man! Every time you plant seed, you sow something that does not come to life [germinating, springing up, and growing] unless it dies first. Nor is the seed you sow then the body which it is going to have [later], but it is a naked kernel, perhaps of wheat or some of the rest of the grains. read more.
But God gives to it the body that He plans and sees fit, and to each kind of seed a body of its own.