Albert Barnes Commentary Ezekiel 25:8

"Thus saith the Lord Jehovah: Because that Moab and Seir do say, Behold, the house of Judah is like unto all the nations;" — Ezekiel 25:8 (ASV)

Prophecies against Moab, which lay south of Ammon, and shared Ammon’s implacable hostility to the children of Israel.

Seir was close to Moab. Edom is identified with Mount “Seir” (Ezekiel 35:1–15); and “Seir” is therefore probably coupled with “Moab” here because, being near neighbors closely leagued together, they expressed a common exultation at Jerusalem’s fall.