23 Curse ye Meroz, said the angel of the LORD, curse ye bitterly the inhabitants thereof; because they came not to the help of the LORD, to the help of the LORD against the mighty.
[AD 420] Jerome on Judges 5:23
(Judges 5:23) Cursed be the land of Meroz, said the Angel of the Lord. In Hebrew it is written: Curse Meroz, said the Angel of the Lord. The Angel of the Lord is understood by the Hebrews to be Michael, who commands Deborah to have the people of Israel curse Meroz, that is, the power of the Angel that presided over the Canaanites. For Meroz is interpreted as secret. Therefore, he is commanded to be cursed, that is, anathematized, because while the other angels fought for Israel, he not only did not fight, but also persevered in their adversity. Curse the inhabitants of Meroz, says the Lord’s angel. Curse them bitterly because they did not come to help the Lord. They did not come to help the strong Lord.

[AD 1781] Richard Challoner on Judges 5:23
Meroz: Where this land of Meroz was, which is here laid under a curse, we cannot find: nor is there mention of it anywhere else in holy writ. In the spiritual sense, they are cursed who refuse to assist the people of God in their warfare against their spiritual enemies.