John Calvin Commentary Isaiah 38:19

"The living, the living, he shall praise thee, as I do this day: The father to the children shall make known thy truth." — Isaiah 38:19 (ASV)

The living, the living, he shall confess you. He does not include all people without exception, for many live, who yet extinguish the glory of God by their ingratitude, as far as lies in their power, and undoubtedly have nothing further from their thoughts than that they were born to praise God. But he simply declares that people, as long as God supports them in this life, may justly be regarded as the lawful heralds of his glory when he invites them, by his kindness, to fulfill that role. And this contrast shows that the statement he made a little earlier, that “in death or in the grave there is no remembrance of God,” is a general declaration that those who would willingly be employed in praising God are deprived of this favor when they are removed from the world.

As I do this day. He solemnly declares that he will be one of the witnesses of the glory of God, and this gives a clear indication of gratitude toward God.

For he declares that he will not be forgetful, but will continually give thanks to God and will make known the favor he has received. He intends to do this not only for the people of his own age but also for posterity, so that they too may celebrate those praises and adore the author of such a great favor.

The father shall make known to the sons your truth. From this we should learn a useful lesson: children are given to men on the express condition that every man, by instructing his children, should endeavor to the best of his ability to transmit the name of God to posterity.

Therefore, fathers of families are especially instructed to be careful in this regard, that they should diligently mention the benefits God has bestowed on them.

By the word truth, he means that faithfulness which God shows toward his people, and all the testimonies of his grace by which he proves that he is true.