23 For the LORD will pass through to smite the Egyptians; and when he seeth the blood upon the lintel, and on the two side posts, the LORD will pass over the door, and will not suffer the destroyer to come in unto your houses to smite you.
We must also inquire who that being was of whom it is said in Exodus that he wished to kill Moses because he was setting out for Egypt. And afterwards, who is it that is called the “destroying angel”? And who also is he who in Leviticus is described as Apopompeus, that is, the Averter, of whom the Scripture speaks thus: “One lot for the Lord, and one lot for Apopompeus”?
And who else could be the destroyer in Exodus, which Moses wrote, except the one who is the cause of destruction to those who obey him and who do not resist and struggle against his wickedness?
I cull these few flowers in passing from the fair field of the Holy Scriptures. They will suffice to warn you that you must shut the door of your breast and fortify your brow by often making the sign of the cross. Thus alone will the destroyer of Egypt find no place to attack you. Thus alone will the firstborn of your soul escape the fate of the firstborn of the Egyptians. Thus alone will you be able with the prophet to say, “My heart is fixed, O God, my heart is fixed; I will sing and give praise.”
[The Son of God’s] cross is our victory, and his gibbet is our triumph. With joy let us take this sign on our shoulders, let us bear the banners of victory. Let us bear such an imperial banner, indeed, on our foreheads! When the devil sees this sign on our doorposts, he trembles. Those who are not afraid of gilded temples are afraid of the cross, and those who disdain regal scepters and the purple and the banquets of the Caesars stand in fear of the loneliness and the fasts of the Christian.
This [cross] we have been given as a sign on our forehead, just as Israel was given the circumcision. For by it we faithful are set apart from the infidels and recognized. It is a shield and armor and a trophy against the devil. It is a seal that the destroyer may not strike us, as Scripture says.
[AD 253] Origen of Alexandria on Exodus 12:23