43 But let us endeavour to assist those souls which fail in their faith through reasons drawn from nature. If one should mix different sorts of seeds together and sow them indiscriminately in the earth, will not the grain of each several kind, wherever it may have been thrown, shoot forth at the proper time in accordance with its own specific nature so as to reproduce the condition of its own form and its own body.
Thus then the substance of each individual flesh, though its particles have been variously and diversely scattered, has within it an immortal principle, since it is the flesh of an immortal soul, and at the time which God in His good pleasure shall appoint, there will be collected from the earth and drawn to it, its own component particles, which will be restored to that form which death had formerly dissolved. And thus it will come to pass that to each soul will be restored, not a confused or foreign body but its own which it had when alive, in order that the flesh together with its own soul may for the conflicts of the present life either be crowned if undefiled, or punished if defiled. And accordingly our Church, in teaching the faith instead of “the Resurrection of the flesh,” as the Creed is delivered in other Churches, guardedly adds the pronoun “this”— “the resurrection of this flesh.” “Of this,” that is, no doubt, of the person who rehearses the Creed, making the sign of the cross upon his forehead, while he says the word, that each believer may know that his flesh, if he have kept it clean from sin, will be a vessel of honour, useful to the Lord, prepared for every good work; but, if defiled by sins, that it will be a vessel of wrath destined to destruction.
But now, concerning the glory of the resurrection and the greatness of the promise by which God has bound Himself, if any one desires to be more fully informed, he will find notices in almost all the divine volumes, out of which, simply by way of bringing them to remembrance, we will mention a few passages in the present place, and then make an end of the work which you have enjoined. The Apostle Paul makes use of such arguments as the following in asserting that mortal flesh will rise again. “But if there be no resurrection of the dead, then is not Christ risen. And if Christ be not risen, our preaching is vain and your faith is vain.” And presently afterwards, “But now is Christ risen from the dead, the first-fruits of them that sleep. For since by man came death, by man came also the resurrection of the dead. For as in Adam all die, even so in Christ shall all be made alive. But every man in his own order. Christ the first-fruits, afterwards they that are Christ's at His coming, then comes the end.” And afterways he adds, “Behold I show you a mystery: We shall all rise indeed, but we shall not all be changed;” or as other copies read, “We shall all sleep, indeed but we shall not all be changed; in a moment, in the twinkling of an eye, at the last trump; for the trumpet shall sound, and the dead shall rise incorruptible, and we shall be changed.” However, whichever be the true text, writing to the Thessalonians, he says, “I would not have you ignorant, brethren, concerning those who are asleep, that you sorrow not, as the others who have no hope. For if we believe that Jesus died and rose again, so those also who sleep through Jesus shall God bring with Him. For this we say unto you by the word of the Lord, that we who are alive and remain at the coming of the Lord shall not prevent them that sleep. For the Lord Himself shall descend from heaven with a shout, with the voice of the archangel, with the trump of God, and the dead who are in Christ shall rise first: then we who are alive and remain shall be caught up together with them in the clouds to meet Christ in the air, and so shall we ever be with the Lord.”
Source: Commentary on the Apostles' Creed (New Advent)