John Calvin Commentary Isaiah 38:16

"O Lord, by these things men live; And wholly therein is the life of my spirit: Wherefore recover thou me, and make me to live." — Isaiah 38:16 (ASV)

O Lord, even to all who shall live after them. The Prophet's concise style has led to various interpretations. The most commonly received interpretation is "O Lord, they shall live beyond those years," that is, "they shall lengthen their life." This is equivalent to saying, "When you have lengthened my life, you will grant that others also shall enjoy the same favor." But that meaning does not agree with the text, and I consider it forced.

I rather think that Hezekiah’s meaning was this: "O Lord, whoever shall live beyond those years, to them also will the life of my spirit be known." We must therefore supply the relative אשר, (asher), who, as Hebrew writers frequently do, and there will be nothing forced in this interpretation. For there can be no doubt, and nobody denies it, that he speaks of the years which the Lord had extended for him. Thus he means that this favor will be acknowledged not only by the people of that age but also by posterity.

And didst cause me to sleep, and didst make me alive. In this way he magnifies the greatness of the favor, because it will also be well known to a future age and will continue to be engraved on the memory of all, even when Hezekiah himself is dead, and not only so, but will be regarded as a kind of resurrection. By the word sleep he means death, as the Scriptures frequently do (1 Corinthians 11:30; 1 Thessalonians 4:14; 2 Peter 3:4). Thus he compares this mortal disease to death, for he was so near death that he utterly despaired of life.