John Trapp on Isaiah 34:5

Ver. 5. For my ſword ſhall be bathed in heaven] Heb. drunk or drenched, i. e. In caelo decretum eſt ut inebrietur; whence-ſoever the ſword comes, it is bathed in Heaven, hath its commiſſion from God, Jer. 47.6, 7. See Jer. 46.9. and as a drunken man reeleth to and fro: ſo the ſword, when once in commiſſion, roveth up and down, and rideth circuit uſually, Ezek. 14.17.

Behold it ſhall come down upon Idumea] i e. Upon the Edomites who were aſſidui & acerrimi hoſtes Judaeorum, bitter enemies to the Jews, though both Nations came of Iſaac, both were circumciſed: ſo are now the Romiſh Edomites to the Churches of Chriſt, with whoſe blood they are red all over, Rev. 17. The Hebrews underſtand here by Idumea, Rome.