"And I am like a moth to Ephraim, and like rottenness to the house of Judah." LXX: "And I am like a tribulation to Ephraim, and like a stimulus to the house of Judah." In the Hebrew language "moth" is called "Recob" for "rot and decay"; one of which consumes clothes and the other wood: for which the LXX translated as "turbulence", which is "disorder" or "turbulence", and "stimulus". And it should be noted that the moth pertains to Ephraim, and the rottenness to the house of Judah. Therefore, how does a clothes moth consume clothing, and decay or rot consume wood; which both take a long time: In the same way, God gave a place for repentance to the ten tribes, and later to the two tribes for a long time, calling them to salvation, storing up His wrath for the day of wrath, like a moth or decay, not because God is a moth or decay, disturbance or affliction, but because to those who suffer punishment all these things seem so. Therefore, first consumed was Ephraim and Israel, then followed was the house of Judah: not Judah himself, but his house; otherwise, it was reserved for the genealogy of Judah, among whom He had been placed: And He was the expectation of the nations. However, the heretics, who are understood to be Ephraim, and also Judas, namely, those who remain with the Church, and who are contained in the errors or vices of heretics, will be subject to the same judgment.
Just as the moth consumes clothing and decay or dry-rot consumes wooden things (which both occur over a long time), in the same manner God, giving a place of penitence over a long time to the ten tribes and then afterward to the two tribes—summoning to salvation those who treasure for themselves wrath for the day of wrath—becomes like a moth or rot.
[AD 420] Jerome on Hosea 5:12