But I will have mercy upon the house of Judah - I will spare them as a kingdom after Israel has been carried away into captivity by the Assyrians.
And will save them by the Lord their God - Remarkably fulfilled in the supernatural defeat of the army of the Assyrians, see 2 Kings 19:35; and so they were saved not by bow, nor by sword, nor by battle, nor by horses, nor by horsemen. The former expression may mean, not in war by horses, i.e., yoked to war chariots, nor by horsemen - nor by cavalry, however efficient such troops might have then been deemed.
I will have mercy on the house of Judah - For to them the promises were made in David, and of them, according to the flesh, Christ was to come. Israel, moreover, as being founded in rebellion and apostasy, had gone on from bad to worse. All their kings clave to the sin of Jeroboam; not one did right in the sight of God; not one repented or hearkened to God. Whereas Judah, having the true Worship of God, and the reading of the law, and the typical sacrifices, through which it looked on to the great Sacrifice for sin, was on the whole, a witness to the truth of God (see the note at Hosea 11:12).
And will save them by the Lord their God, not by bow - Shortly after this, God did, in the reign of Hezekiah, save them by Himself from Sennacherib, when the Angel of the Lord smote in one night 185,000 in the camp of the Assyrians. “Neither in that night, nor when they were freed from the captivity at Babylon, did they bend bow or draw sword against their enemies or their captors. While they slept, the Angel of the Lord smote the camp of the Assyrians. At the prayers of David and the prophets and holy men, yea, and of the angels Zechariah 1:12 too, the Lord stirred up the spirit of Cyrus king of Persia, to set them free “to go up to Jerusalem, and build the temple of the Lord God of Israel” Ezra 1:3. But much more, this is the special promise of the Gospel, that God would deliver, not outwardly, but inwardly; not by human wars, but in peace; not by man, but by Himself. “By the Lord their God,” by Himself who is speaking, or, The Father by the Son, (in like way as it is said, “The Lord rained upon Sodom fire from the Lord” Genesis 19:24).
They were saved in Christ, the Lord and God of all, not by carnal weapons of warfare, but by the might of Him who saved them, and shook thrones and dominions, and who by His own Cross triumpheth over the hosts of the adversaries, and overthroweth the powers of evil, and giveth to those who love Him, “to tread on serpents and scorpions and all the power of the enemy.” They were saved, not for any merits of their own, nor for anything in themselves. But when human means, and man‘s works, such as he could do of his own free-will, and the power of his understanding, and the natural impulses of his affections, had proved unavailing, then he redeemed them by His Blood, and bestowed on them gifts and graces above nature, and filled them with His Spirit, and gave them “to will and to do of His good pleasure.” But this promise also was, and is, to the true Judah, i. e., to those who, as the name means, “confess and praise” God, and who, receiving Christ, who, as Man, was of the tribe of Judah, became His children, being re-born by His Spirit.”