Leviticus 16:8

I will however mention the sacrifice in which two goats were offered, the one being slain and the other let go. In these two goats there is an anticipative image of the two natures of the Savior; in the one let go, of the impassible Godhead, in the one slain, of the passible manhood.

May I offer, moreover, an interpretation of the two goats which were presented on "the great day of atonement"? Do they not also prefigure the two natures of Christ? They were of like size and very similar in appearance, owing to the Lord's identity of aspect. He is not to come in any other form. He had to be recognized by those by whom he was also wounded and pierced. One of these goats was bound with scarlet and driven by the people out of the camp into the wilderness, amid cursing, and spitting, and pulling and piercing, being thus marked with all the signs of the Lord's own passion. The other, by being offered up for sins and given to the priests of the temple for meat, afforded proofs of his second appearance, when (after all sins have been expiated) the priests of the spiritual temple, that is, the church, are to enjoy the flesh, as it were, of the Lord's own grace. The rest will deport from salvation without tasting it.

About the two goats, one that had to be immolated and the other that had to be sent to the desert, called by the Greeks apopompaion, there is usually discussion, and some say that the one that should be immolated must be interpreted in a good way, and the that had to be sent to the desert must be interpreted in the bad. But this interpretation can not be sustained, precisely because when the man who brought the goat with his hand to the desert returns, he is ordered to wash his clothes and his body with water and thus enter the camp ( Cf Lv 16,26 ) as if this were also an indication for interpreting in a bad sense the matter of the goat, from whose contagion man had to be cleansed; but it is also said that those who take the flesh of the other goat and the bull and wash them outside the camp must be washed, because it is commanded that this be done with the goat and the bull, and that once immolated it is done sprinkling with their blood (Cf Lv 9,8-12) and offering both as a sacrifice for sins. And for that reason, the distinction between these two goats must be considered carefully from the allegorical meaning. Similarly, when the tenth day of the seventh month is established as Saturday of Saturdays (Cf Lv 16,29-32) so that the one priest who succeeds his father would do the purification mentioned above, the Scripture says, when speaking of that priest: He will make atonement for the saint of holy. And I do not know if the phrase should be interpreted in any other way than this one: "He will make atonement in the saint's saint", thinking that it is a way of expressing himself. He will do it, then, in that holy place where only the high priest entered, a place that was beyond the veil, where was the ark of the covenant and the altar of incense. Naturally, he will not make the atonement of that place as if it were God, but he will make the atonement there to God, that is why it is said: He will make atonement for the saint of the saint. In Greek, this phrase is also placed in neutral gender: tò agion tou agíou. Or is it perhaps the Holy Spirit of the holy God, that is to say: tò agion pneuma tou agíou zeou? Or will "make atonement" not be rather "making atonement purify"? Because the words are united like this: And he will make atonement for the saint of the saint and for the tabernacle of the testimony and will make atonement for the altar and make…