God of David (Hebrew. Elohim. This tells us the nature of Hezekiah's prayer. He had no heir to the throne, but remembered Jehovah's word to David in 2 Samuel 7:12-16. Hence his anxiety, as manifested in his "Songs of the degrees". Compare Psalms 127:3-5; Psalms 138; Psalms 132. See App-67. (Manasseh not born till three years later, 600 B.C.)
behold. Figure of speech Asterismos. Introducing the fivefold (App-10) promise and answer to his prayer in verses: 2 Kings 20:5 and 2 Kings 20:6.
go up, &c. This also must have been. subject of prayer.