Of thy sons that shall issue from thee. Hezekiah had at the time, probably, no son, since Manasseh, who succeeded him upon the throne, was not born till two years later. Besides Manasseh, he appears to have had a son, Amariah, who was an ancestor of the Prophet Zephaniah (Zephaniah 1:1).
He may, of course, have also had others. His descendants, rather than his actual sons, seem to be here intended; and the fulfilment of the prophecy is to be found in Daniel 1:3, where certain "of the king's seed" are mentioned among the Israelites who served as eunuchs in the palace of Nebuchadnezzar.