2 Kings 19:4 - Matthew Poole's English Annotations on the Holy Bible

It may be; he speaks doubtfully, because he knew not whether God would not deliver them all up into the Assyrian's hand, as he and his people deserved. But sometimes this is not a word of doubt, but of good hope; as Numbers 22:33 Joshua 14:12. The Lord thy God, to whom thou art dear and precious. He saith not our God, because he seemed to have forsaken and rejected them; and they by their designs had forfeited all their interest in him. Will hear, i.e. will show by his actions that he hath heard them with just indignation. Will reprove the words, or rather, will reprove him (an ellipsis of the pronoun, which is frequent in the Hebrew tongue) for the words, as the Syria, and Arabic, and Chaldee render it. Lift up thy prayer for the remnant: this he mentions as an argument to stir up Isaiah to pray, and to move God's compassion towards them; that they were but a small remnant, either of God's people, of whom ten tribes were now lost; or of the kingdom of Judah, which had been greatly wasted and depopulated in the days of Ahaz, and now lately by this Assyrian, 2 Kings 19:13.