Isaiah 38:19

"For from this day I shall beget children who will announce your righteousness." Some say that he promises to institute a choir [chorostasia] and to appoint chanters of psalms with good voices in the temple. Others, who pay attention to more esoteric things, say that Hezekiah, since he thought on a high plane, was of the opinion that he would have a kingdom without end and unceasing life. For he was persuaded that the writings concerning the son of David destined to be the Christ were said about himself. Hence they say, although he was in the fifteenth year of his reign he does not seem to have procreated children. Accordingly, on learning that his end was near, he pays attention to the question of his successors and adds with reference to his children that they will announce the righteousness of the Lord. However, this statement was not verified since. Manasseh was wicked and impious.

(Verse 19) Living, the living himself will confess to you, as I do today. The father will make your truth known to the children. The living, the living themselves will confess to you, just as I do today. And this confession is set forth for praise. For he does not confess his own crimes, but gives thanks to God; and there is no beautiful praise on the mouth of a sinner (Sirach 15). And when Hell and death do not confess or praise God, on the contrary, life and the living glorify the Lord. And what follows: The Father will make your truth known to your children, this signifies what is said in Deuteronomy: Ask your father, and he will tell you; your elders, and they will inform you (Deuteronomy 32, 7), so that God's mercy may be proclaimed to posterity through successions and individual generations. For this reason the LXX translate it: 'From today I will beget sons who will announce your righteousness.' And the causal conjunction connects the following with what came before: that indeed, living beings and he himself, who will beget sons from this day, might bless God, because it was certainly not within their power. For those children were not promised through the prophet, but rather through the present life. Especially since Manasseh, the most impious son, was born, who filled Jerusalem with blood from gate to gate, and did not bless but cursed God, persecuting his saints. Therefore we can say according to the Septuagint that he said, 'I will make children' instead of 'sons': but by 'children' we understand either little ones, or young boys, or infants and later generations, so that all future posterity, knowing this, may praise his incredible mercy which he has obtained.