Those who were righteous before and under the law shall be saved by Christ
Trypho: If I seem to interrupt these matters, which you say must be investigated, yet the question which I mean to put is urgent. Allow me first.
Justin: Ask whatever you please, as it occurs to you; and I shall endeavour, after questions and answers, to resume and complete the discourse.
Trypho: Tell me, then, shall those who lived according to the law given by Moses, live in the same manner with Jacob, Enoch, and Noah, in the resurrection of the dead, or not?
Justin: When I quoted, sir, the words spoken by Ezekiel, that 'even if Noah and Daniel and Jacob were to beg sons and daughters, the request would not be granted them,' but that each one, that is to say, shall be saved by his own righteousness, I said also, that those who regulated their lives by the law of Moses would in like manner be saved. For what in the law of Moses is naturally good, and pious, and righteous, and has been prescribed to be done by those who obey it; and what was appointed to be performed by reason of the hardness of the people's hearts; was similarly recorded, and done also by those who were under the law. Since those who did that which is universally, naturally, and eternally good are pleasing to God, they shall be saved through this Christ in the resurrection equally with those righteous men who were before them, namely Noah, and Enoch, and Jacob, and whoever else there be, along with those who have known this Christ, Son of God, who was before the morning star and the moon, and submitted to become incarnate, and be born of this virgin of the family of David, in order that, by this dispensation, the serpent that sinned from the beginning, and the angels like him, may be destroyed, and that death may be contemned, and for ever quit, at the second coming of the Christ Himself, those who believe in Him and live acceptably,—and be no more: when some are sent to be punished unceasingly into judgment and condemnation of fire; but others shall exist in freedom from suffering, from corruption, and from grief, and in immortality.
Source: Dialogue with Trypho (New Advent)