Isaiah 38:9

The writing of Hezekiah— We have here an example of the piety of king Hezekiah, like a true son of David, singing to his harp (for it appears from Isaiah 38:20 that this was a song fitted to that instrument) and pouring forth his sacred meditations as was usual among the pious of this nation. Grotius is of opinion, that this song was dictated by Isaiah; Vitringa, however, thinks that there is something in it more involved and less sublime than in the writings of Isaiah.