We, therefore, do not maintain that the body which has undergone corruption resumes its original nature, any more than the grain of wheat which has decayed returns to its former condition. But we do maintain, that as above the grain of wheat there arises a stalk, so a certain power is implanted in the body, which is not destroyed, and from which the body is raised up in incorruption. The philosophers of the Porch, however, in consequence of the opinions which they hold regarding the unchangeableness of things after a certain cycle, assert that the body, after undergoing complete corruption, will return to its original condition, and will again assume that first nature from which it passed into a state of dissolution, establishing these points, as they think, by irresistible arguments. We, however, do not betake ourselves to a most absurd refuge, saying that with God all things are possible; for we know how to understand this word “all” as not referring either to things that are “non-existent” or that are inconceivable.
But we maintain, at the same time, that God cannot do what is disgraceful, since then He would be capable of ceasing to be God; for if He do anything that is disgraceful, He is not God. Since, however, he lays it down as a principle, that “God does not desire what is contrary to nature,” we have to make a distinction, and say that if any one asserts that wickedness is contrary to nature, while we maintain that “God does not desire what is contrary to nature,”— either what springs from wickedness or from an irrational principle—yet, if such things happen according to the word and will of God, we must at once necessarily hold that they are not contrary to nature.
Therefore things which are done by God, although they may be, or may appear to some to be incredible, are not contrary to nature. And if we must press the force of words, we would say that, in comparison with what is generally understood as “nature,” there are certain things which are beyond its power, which God could at any time do; as, e.g., in raising man above the level of human nature, and causing him to pass into a better and more divine condition, and preserving him in the same, so long as he who is the object of His care shows by his actions that he desires (the continuance of His help).
Source: Against Celsus (New Advent)