In his First Apology, Justin Martyr wrote the following, affirming creation ex materia:
But we have received by tradition that God does not need the material offerings which men can give, seeing, indeed, that He Himself is the provider of all things. And we have been taught, and are convinced, and do believe, that He accepts those only who imitate the excellences which reside in Him, temperance, and justice, and philanthropy, and as many virtues as are peculiar to a God who is called by no proper name. And we have been taught that He in the beginning did of His goodness, for man's sake, create all things out of unformed matter; and if men by their works show themselves worthy of this His design, they are deemed worthy, and so we have received--of reigning in company with Him, being delivered from corruption and suffering. For as in the beginning He created us when we were not, so do we consider that, in like manner, those who choose what is pleasing to Him are, on account of their choice, deemed worthy of incorruption and of fellowship with Him. For the coming into being at first was not in our own power; and in order that we may follow those things which please Him, choosing them by means of the rational faculties He has Himself endowed us with, He both persuades us and leads us to faith. And we think it for the advantage of all men that they are not restrained from learning these. (First Apology X [ANF: 1:165], emphasis added)
The underlying Greek is εξ αμορφου υλης, and refers to matter (which pre-exists the act of divine creation) without form. Justin is an early witness to the doctrine of creation being out of pre-existing material, not ex nihilo.
My friend, Blake Ostler, has written the article supporting the Latter-day Saint doctrine of creation ex materia and refutation of creation ex nihilo, which is a must-read:
