1 Corinthians 15:39
All flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds. All flesh is not the same flesh: but there is one kind of flesh of men, another flesh of beasts, another of fishes, and another of birds.
This verse belongs to the discussion of the resurrection of the body. It distinguishes four kinds of flesh, those of humans, land animals, fishes, and birds. The difference among these kinds of flesh shows that bodies differ in their organization.
Resurrection does not require the same particles of matter from the mortal body to form the immortal body, since identity rests in organization rather than in identical matter. The resurrection is necessary because the dead sleep in the grave as whole beings and do not receive their final reward or punishment at death, but await the future resurrection and judgment. The surrounding passage uses the planting and growth of seed to teach both the resurrection of the body and the renewing of the heart.
As the human agent plants the seed and God waters it and causes the sun to shine on it until the blade springs up, so God brings new life. Development in earthly things is given to teach spiritual things.