The living, the living, he shall praise you, as I do this day: the father to the children shall make known your truth.
Read Chapter 38
Athanasius the Apostolic
AD 373
[Those who live in a godly manner] and participate in such goodness are the only ones able to give glory to God, and that is what really constitutes a feast and a holy day. For the feast is not indulging in a lot of food or dressing up in lovely clothes. It is not enjoying days of leisure. It is acknowledging God and offering thanksgiving and songs of praise to him. But this belongs to the saints alone, who live in Christ.… That is the way it was with Hezekiah, who was delivered from death and therefore praised God, saying, “Those who are in hell cannot praise you; the dead cannot bless you; but the living shall bless you, as I do today.” - "Festal Letter 7.3"
“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. - "Commentary on Isaiah 3.4.38"
For the netherworld and death will neither confess nor praise you, according to what is written: “In the netherworld, who will confess you?” Confession in this instance, moreover, is received not as an act of penance but as an offering of glory and praise, as we read in the Gospel: “I praise you Lord, Father of heaven and earth.” He also says: “They who descend to the pit will not hope for your truth,” which is better than the Septuagint’s “will not hope for your mercy.” For he who is in the grave hopes not for the truth of judgment but for the mercy of God, ultimately when the Savior will descend to the netherworld to liberate the captives from it. - "Commentary on Isaiah 11.38"