thresh - destroy thy foes “gathered” by Jehovah as “sheaves” (Isa 41:15, Isa 41:16).
thine horn - Zion being compared to an ox treading corn, and an ox’s strength lying in the horns, her strength is implied by giving her a horn of iron (compare 1Ki 22:11).
beat in pieces many - (Dan 2:44).
I will consecrate their gain unto the Lord - God subjects the nations to Zion, not for her own selfish aggrandizement, but for His glory (Isa 60:6, Isa 60:9; Zec 14:20, with which compare Isa 23:18) and for their ultimate good; therefore He is here called, not merely God of Israel, but “Lord of the whole earth.”