The Hebrew word aggaph (אַגָּף) refers to the wing or flank of an army. In military contexts it denotes the flanking forces of a battle formation. In natural contexts it can mean the edge or side of something.
The imagery of wings in Hebrew Scripture is profoundly protective and divine. Though aggaph specifically refers to army flanks, it belongs to the rich wing-vocabulary of the Old Testament. God's wings (kanaph) shelter His people (Psalm 91:4, Ruth 2:12), and the great cherubim spread their wings over the ark (Exodus 25:20). Military wings speak of the disciplined, coordinated protection of a force working together — an earthly reflection of how God marshals all things for the protection of His covenant people. Israel's army, when ordered by God, became an extension of His providential wing.