Isaiah 31. The Folly of Reliance on Egypt. Jerusalem will be Protected, and Assyria Overthrown.
vv. Isaiah 31:6 f. seems to be an interpolation. Isaiah 31:4 f. creates serious difficulties. Isaiah 31:4 apparently represents Yahweh as attacking (mg.) Zion, undismayed by its rulers as a lion is undismayed by the shepherds, whereas Isaiah 31:5, with an abrupt change of metaphor, represents Him as Jerusalem's protector. By drastic measures we can remove the discrepancy; the passage then represented Yahweh either as hostile to Jerusalem or as its protector. Of the two the latter is preferable, but it involves the omission of so shall.. As birds fly. If we keep the text as it stands, the meaning seems to be that Yahweh will wrest Jerusalem from its present rulers, but will protect it from falling into the hands of the Assyrians, who are the instruments of His judgment. This is continued in Isaiah 31:8 f., which represents the Assyrians as smitten down by His power rather than by human antagonists.
Woe to those who trust in Egypt and her cavalry and not in Yahweh. For Yahweh is wise as well as the sapient politicians, and His threat of evil will certainly be fulfilled. For Egypt, weak and perishable, is no match for Yahweh, who is spirit, and will involve helper and helped in one common disaster. When He descends to fight against Zion, the Egyptians will be as powerless to rescue it as the shepherds to rescue the prey from the dauntless lion. Yahweh will protect Jerusalem as birds protect their young. Let the disobedient turn to Him. In the day of deliverance all will cast away their idols. The Assyrian shall fall by no human hand, he shall flee in panic.
Isaiah 31:3. A classical passage for the OT sense of flesh. It is the weak and mortal in contrast with the immortal and omnipotent. Flesh stands not for the lower element in human nature in contrast with the higher (as in Romans 7:7-25), but for man as a whole as contrasted with the immortals (Genesis 6:3).
Isaiah 31:8 b. This modification of 8 a may be an insertion.
Isaiah 31:9. his rock: the parallelism suggests that this means the Assyrian king. This is improbable; AV renders and he shall pass over to his strong hold for fear. Duhm 2 renders his rock by reason of terror shall he pass by, i.e. the hunted animal in its terror passes by its usual shelter. Duhm 3 emends, reading, and his heroes shall be dislodged from the siege works.