Thematic Bible: Why the body dies

And if Christ is in you, the body is dead because of sin; but the spirit is life because of righteousness. But if the Spirit of him that raised up Jesus from the dead dwelleth in you, he that raised up Christ Jesus from the dead shall give life also to your mortal bodies through his Spirit that dwelleth in you.

But some one will say, How are the dead raised? and with what manner of body do they come? Thou foolish one, that which thou thyself sowest is not quickened except it die: and that which thou sowest, thou sowest not the body that shall be, but a bare grain, it may chance of wheat, or of some other kind; read more.
but God giveth it a body even as it pleased him, and to each seed a body of its own.