Syrians - Though now allies of Ephraim, after Rezin’s death they shall join the Assyrians against Ephraim. “Together,” in Isa 9:11, refers to this. Conquering nations often enlist in their armies the subject races (Isa 22:6; compare 2Ki 16:9; Jer 35:11), [Aben Ezra, Gesenius]. Horsley less probably takes “Syrians before,” as the Syrians to the east, that is, not Rezin’s subjects, but the Assyrians: “Aram” being the common name of Syrians and Assyrians.
Philistines - of Palestine.
behind - from the west: in marking the points of the compass, Orientalists face the east, which is before them: the west is behind. The right hand is the south: the left, the north.
devour - as a ravenous beast (Isa 1:20; Jer 10:25; Jer 30:16; Num 14:9).