Wisdom 18:2

For the saints of God there was the greatest light, when they were illuminated both outwardly by bodily light and inwardly by spiritual radiance; for the faith of God and the purity of conscience enlightened them within, whose voices the enemies heard, but whose appearance they did not see, because darkness blinded their eyes, and because, by the temptation of the plagues which came upon the Egyptians, these were not struck, but were led by heavenly guidance through the pillar of fire at night and the pillar of cloud by day, and gave worthy thanks to their Creator. Therefore, since those holy fathers who lived under the Old Testament bore the type of the saints who serve Christ under the New Testament; those in historical Egypt labored afflicted under Pharaoh, while the persecution of the Devil in the world burdens these with tribulations; for the greatest light shines for those who diligently carry the true light, which enlightens every man coming into this world, in the dwelling of their heart. Indeed, the enemies hear the voice of their preaching, but do not recognize the form of the truth that is in them, and therefore do not believe them. Both the pillar of fire at night and the pillar of cloud by day lead them, because the incarnation of Christ always protects them with the shield of His protection in adversity and prosperity.

And those who before had been harmed, namely by Pharaoh oppressing and scourging them, as is clear from Exodus 1. Because they were not harmed, namely by the plagues inflicted by God, they gave thanks to you: Isaiah 51: "Joy and gladness shall be found therein, thanksgiving and the voice of praise." And that there might be a distinction, namely between themselves and the Egyptians; they sought you, O God, or: they prayed to you, O God, according to that verse of the Psalm: "Judge me, O God, and distinguish my cause from an unholy nation," just as Abraham also asked that the just man not be destroyed like the impious: Genesis 18. Or: distinction, namely distance: this was granted to the Israelites when "the Angel, lifting himself up, stood between the camp of the Egyptians and the camp of Israel," as is clear from Exodus 14.