For the LORD will pass through to smite the Egyptians; and when he sees the blood upon the lintel, and on the two side posts, the LORD will pass over the door, and will not allow the destroyer to come in unto your houses to slay you.
All Commentaries on Exodus 12:23 Go To Exodus 12
Jerome
AD 420
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.”