But I will have mercy upon the house of Judah, and will save them by the LORD their God, and will not save them by bow, nor by sword, nor by battle, by horses, nor by horsemen.
But I will have mercy upon the house of Judah. Judah is only incidentally mentioned, to form a contrast to Israel.
And will save them by the Lord their God - more emphatic than 'by myself;' by that Yahweh (me) whom they worship as "their God," whereas ye despise him.
Not ... by bow - on which ye Israelites rely (Hosea 1:5, "the bow of Israel"). Jeroboam II was famous as a warrior (2 Kings 14:25). Yet it was not by their warlike power Yahweh would save Judah (1 Samuel 17:47; Psalms 20:7; Psalms 44:6, "I will not trust in my bow, neither shall my sword save me. But thou hast saved us from our enemies"). The miraculous deliverance of Jerusalem from Sennacherib (2 Kings 19:35), and the restoration from Babylon, are herein predicted. Judah governed by kings of David's line, and having the true worship of God, the temple, and the sacrifices, was to experience a mercy which was denied to Israel, as being founded and governed in apostasy from God. Not one of their kings that did not follow the sin of Jeroboam. the worship of the symbol of God, the calves, and some of them had also fallen into the grossest idolatry, Baal worship, etc.