As birds flying - This is another comparison indicating substantially the same thing as the former, that Yahweh would protect Jerusalem. The idea here is, that He would do it in the same manner as birds defend their young by hovering over them, securing them under their wings, and leaping forward, if they are suddenly attacked, to defend them. Our Saviour has used a similar figure to indicate his readiness to have defended and saved the same city Matthew 23:27, and it is possible that he may have had this passage in his eye. The phrase 'birds flying,' may denote the "rapidity" with which birds fly to defend their young, and hence, the rapidity with which God would come to defend Jerusalem; or it may refer to the fact that birds, when their young are attacked, fly, or flutter around them to defend them; they will not leave them.

And passing over - פסוח pâsoach. Lowth renders this, 'Leaping forward.' This word, which is usually applied in some of its forms to the Passover Exodus 12:13, Exodus 12:23, Exodus 12:27; Numbers 9:4; Joshua 5:11; 2 Chronicles 30:18, properly means, as a verb, "to pass over," and hence, to preserve or spare. The idea in the passage is, that Yahweh would protect Jerusalem, as a bird defends its young.

Passing over "Leaping forward" - The generality of interpreters observe in this place an allusion to the deliverance which God vouchsafed to his people when he destroyed the first-born of the Egyptians, and exempted those of the Israelites sojourning among them by a peculiar interposition. The same word is made use of here which is used upon that occasion, and which gave the name to the feast which was instituted in commemoration of that deliverance, פסח pesach. But the difficulty is to reconcile the commonly received meaning of that word with the circumstances of the similitude here used to illustrate the deliverance represented as parallel to the deliverance in Egypt.

"As the mother birds hovering over their young,

So shall Jehovah God of hosts protect Jerusalem;

Protecting and delivering, passing over, and rescuing her."

This difficulty is, I think, well solved by Vitringa, whose remark is the more worthy of observation, as it leads to the true meaning of an important word, which hitherto seems greatly to have been misunderstood, though Vitringa himself, as it appears to me, has not exactly enough defined the precise meaning of it. He says, "פסח pasach signifies to cover, to protect by covering: σκεπασω ὑμας, Septuagint. Jehovah obteget ostium; 'The Lord will cover or protect the door:'" whereas it means that particular action or motion by which God at that time placed himself in such a situation as to protect the house of the Israelite against the destroying angel; to spring forward, to throw one's self in the way, in order to cover and protect. Cocceius comes nearer to the true meaning than Vitringa, by rendering it gradum facere, to march, to step forward; Lexicon in voc. The common meaning of the word פסח pasach upon other occasions is to halt, to be lame, to leap, as in a rude manner of dancing, (as the prophets of Baal did, 1 Kings 18:26), all which agrees very well together; for the motion of a lame person is a perpetual springing forward, by throwing himself from the weaker upon the stronger leg. The common notion of God's passage over the houses of the Israelites is, that in going through the land of Egypt to smite the first-born, seeing the blood on the door of the houses of the Israelites, he passed over, or skipped, those houses, and forbore to smite them. But that this is not the true notion of the thing, will be plain from considering the words of the sacred historian, where he describes very explicitly the action: "For Jehovah will pass through to smite the Egyptians; and when he seeth the blood on the lintels and on the two side posts, Jehovah will spring forward over (or before) the door, ופסח יהוה על הפתח upasach Yehovah al happethach, and will not suffer the destroyer to come into your houses to smite you, "Exo 12:23. Here are manifestly two distinct agents, with which the notion of passing over is not consistent, for that supposes but one agent. The two agents are the destroying angel passing through to smite every house, and Jehovah the Protector keeping pace with him; and who, seeing the door of the Israelite marked with the blood, the token prescribed, leaps forward, throws himself with a sudden motion in the way, opposes the destroying angel, and covers and protects that house against the destroying angel, nor suffers him to smite it. In this way of considering the action, the beautiful similitude of the bird protecting her young answers exactly to the application by the allusion to the deliverance in Egypt. As the mother bird spreads her wings to cover her young, throws herself before them, and opposes the rapacious bird that assaults them, so shall Jehovah protect, as with a shield, Jerusalem from the enemy, protecting and delivering, springing forward and rescuing her; ὑπερβαινων, as the three other Greek interpreters, Aquila, Symmachus, and Theodotion, render it. The Septuagint, περιποιησεται· instead of which MS. Pachom. has περιβησεται, circumeundo proteget, "in going about he shall protect, "which I think is the true reading. - Homer, 2 viii. 329, expresses the very same image by this word: -

Αιας δ' ουκ αμελησε κασιγνητοιο πεσοντος,

Αλλα θεων περιβη, και οἱ σακος αμφεκαλυψε:

" - But Ajax his broad shield displayed,

And screened his brother with a mighty shade."

- Ὁς Χρυσην αμφιβεβηκας.

Il. 1:37

Which the scholiast explains by περιβεβηκας, ὑπερμαχεις, i.e., "Thou who strictly guardest Chryses." - L. On this verse Kimchi says, "The angel of the Lord which destroyed the Assyrians is compared to a lion, Isaiah 31:4, for his strength: and here (Isaiah 31:5) to flying birds, for his swiftness."

As birds flying, so will the Lord of hosts defend Jerusalem,.... As the preceding metaphor expresses the mighty power of God, this his tenderness and affection, as well as his speed and swiftness in the deliverance of his people. As birds in the air, at a distance, especially the eagle, have their eye upon their nests, and their young ones in them, and when in danger fly to their assistance, and hover over them, and about them, to keep off those that would hurt them, or carry them away; so the Lord, on high, sees his people when in distress, and hastens to help them, and does surround, protect, and defend them: thus the Lord did, when Sennacherib with his army besieged Jerusalem; who boasted, with respect to other nations, that he had "found as a nest the riches of the people", and that "there was none that moved the wing against him", Isaiah 10:14 to which it is thought the allusion is here:

defending also he will deliver it; from present distress, the siege of the Assyrian army:

and passing over he will preserve it; passing over the city of Jerusalem to the army of the king of Assyria, that lay encamped against it; and smiting that by an angel with a sudden destruction, preserved the city from the ruin it was threatened with. The allusion is rightly thought to be to the Lord's passing over the houses of the Israelites, when he destroyed the firstborn in Egypt, Exodus 12:23 where the same word is used as here, and nowhere else.

Jehovah suddenly arrests the work of punishment, and the love which the wrath enfolds within itself begins to appear. "Like fluttering birds, so will Jehovah of Hosts screen Jerusalem; screening and delivering, sparing and setting free." The prophet uses the plural, "like fluttering birds," with an object - namely, not so much to represent Jehovah Himself, as the tender care and, as it were, maternal love, into which His leonine fierceness would be changed. This is indicated by the fact, that he attaches the feminine ‛âphōth to the common gender tsippŏrı̄m. The word pâsōăch recals to mind the deliverance from Egypt (as in Isaiah 30:29) in a very significant manner. The sparing of the Israelites by the destroyer passing over their doors, from which the passover derived its name, would be repeated once more. We may see from this, that in and along with Assyria, Jehovah Himself, whose instrument of punishment Assyria was, would take the filed against Jerusalem (Isaiah 29:2-3); but His attitude towards Jerusalem is suddenly changed into one resembling the action of birds, as they soar round and above their threatened nests. On the inf. abs. kal (gânōn) after the hiphil, see Ewald, 312, b; and on the continuance of the inf. abs. in the finite verb, 350, a. This generally takes place through the future, but here through the preterite, as in Jeremiah 23:14; Genesis 26:13, and 1 Samuel 2:26 (if indeed vegâdēl is the third pers. preterite there).

As birds flying, so will the LORD of hosts defend Jerusalem; defending also he will deliver it; and passing over he will preserve it.

31:5 As birds - Which come from above, and so cannot be kept off; which fly swiftly, and engage resolutely, when their young ones are in danger. Passing over - The destroying angel shall pass over Jerusalem.

5. As in the image of "the lion," the point of comparison is the fearless might of Jehovah; so in that of the birds, it is His solicitous affection (De 32:11; Ps 91:4; Mt 23:37).

flying-Rather, "which defend" their young with their wings; "to fly" is a secondary meaning of the Hebrew word [Maurer]. "Hovering over" to protect their young [G. V. Smith].

passing over-as the destroying angel passing over, so as to spare the blood-marked houses of the Israelites on the first passover (Ex 12:13, 23, 27). He passed, or leaped forward [Lowth], to destroy the enemy and to spare His people.

31:1-5 God will oppose the help sought from workers of iniquity. Sinners may be convicted of folly by plain and self-evident truths, which they cannot deny, but will not believe. There is no escaping the judgments of God; and evil pursues sinners. The Lord of hosts will come down to fight for Mount Zion. The Lion of the tribe of Judah will appear for the defence of his church. And as birds hovering over their young ones to protect them, with such compassion and affection will the Lord of hosts defend Jerusalem. He will so defend it, as to secure its safety.