Jerome : (Verse 2) And Hezekiah turned his face to the wall, and prayed to the Lord. And Hezekiah turned his face to the wall, because he could not go to the Temple. To the wall of the Temple, next to which Solomon had built a palace. Or rather, next to Jeremiah, to his heart; who calls the heart a wall, so that with his whole mind he might pray to the Lord. — Commentary on Isaiah