Song of Solomon 1:9

Here in figurative fashion he referred by "Pharaoh" to the implacable foe of our nature, the noxious enemy common to us all whom he drowned in the holy waters of baptism like Pharaoh. My mare, then, which I used when I overwhelmed Pharaoh's chariots, I judge you to resemble since you are close to me and have love for me.… So from the apostolic words we understand the mystical words of the Song, and hear the bridegroom saying, I declare that you, being close to me, and hence called an intimate, getting the name from the fact, are like my mare, which I used when drowning the spiritual Pharaoh with his chariots, and I granted you freedom.

"My horses are with Pharaoh's chariots," it says. The horses of the Lord, that is, the people of the Gentiles, were formerly with Pharaoh's chariots, that is, in the power of the devil, since they had not yet believed in Christ. He forewarns them, therefore, not to submit themselves again to that yoke through contempt of the faith. For, as I have already said, the people of the Gentiles who required horses were held under the Pharaoh's yoke, that is, with the chariots of the devil, before the Lord's advent, even though the Lord already foreknew them to be his own. But there is no doubt that the Pharaoh is the devil, for the devil tyrannizes the world like the Pharaoh did Egypt. Moreover, just as the Pharaoh persecuted the sons of Israel, so does the devil persecute the saints in this world.… Yet, now liberated by the grace of Christ from the yoke of tyrannical servitude, having been made sons of God through faith, and destined for celestial glory with a pure heart and true devotion in all holiness and righteousness, let us hold firmly to the same faith through which we live and are saved.

I have likened you, my friend, to my horse-drawn chariots of Pharaoh. For indeed, He calls His cavalry the army of the children of Israel, whom He freed from Egyptian bondage, leading them across the Red Sea into the desert, and brought into the land of the inheritance promised long ago, while the chariots of Pharaoh, which pursued them and wanted to drag them back to servitude, were drowned in the same sea. He calls it a cavalry because just as a charioteer is accustomed to presiding over his cavalry, so the Lord Himself then presided over that people, governing and leading them through the path of salvation. And He compared His Church, which He made His friend through the water of regeneration, to that cavalry: for just as the people were indeed greatly terrified by the approaching chariots of Pharaoh, but were nevertheless saved by heavenly protection, so He has always taught the Church to trust in His protection amidst the threats of persecutors. For even the fact that a pillar of fire then illuminated the people of God, while thick darkness overshadowed the Egyptian troops, so that throughout the whole night they couldn't approach each other; this too never ceases to happen in the night of this age, when the divine dispensation, separating the just from the reprobate with precise judgment, illuminates the just with His grace, but leaves the others in the deserved blindness. And even this, when they came to the Red Sea, the children of Israel were freed with the waters divided, while the Egyptians, with the waters returning upon them, were drowned with their horses and chariots, is it not evident that the very wave of death, which will face all mortals, carries the wicked to destruction, but opens the path to salvation for the pious? The other events too, which we read happened to the cavalry of God, that is, the people of Israel, during the time of the Egyptian persecution, are found, the more diligently they are explained, the more clearly they reveal themselves as a foreshadowing in the holy universal Church, of which that was a part. And since it is taught in this verse how the Lord protects the Church amidst adversities, it remains to be shown how much the Church itself maintains the love of the same Lord and protector in the face of adversities. It is added: