How is it possible for the body that has decomposed to return and be reunited with the soul?

If God created the body from dust, He is quite capable re-creating it after it has decomposed. St. Paul uses the analogy of the grain, which is planted in the earth, decomposes, and then flourishes into a tree: “what you sow is not made alive unless it dies. And what you sow, you do not sow that body that shall be, but mere grain—perhaps wheat or some other grain. But God gives it a body as He pleases, and to each seed its own body” (1 Cor. 15:36–38).