John Calvin Commentary Isaiah 38:9

"The writing of Hezekiah king of Judah, when he had been sick, and was recovered of his sickness." — Isaiah 38:9 (ASV)

The writing of Hezekiah. Though sacred history gives no account of this writing, yet it deserves to be recorded and is highly worthy of observation, for we see that Hezekiah was unwilling to pass in silence or to bury in forgetfulness so remarkable a blessing which he had received from God.

By his example he shows what all believers ought to do when God miraculously and in an unusual manner exerts his power on their behalf. They ought to make known their gratitude not only to their contemporaries but also to posterity, as we see that Hezekiah did by this song, which may be regarded as a public record. We see that David composed many psalms on this subject when he had been delivered from very great dangers, so that he took care to celebrate until the end of the world what was worthy of being remembered by all ages. (Psalms 18:2 and Psalm 27:1)

Especially, the more eminent any person is, and the higher the station which they occupy, the more they are bound to consider themselves as placed by God on a theater and enjoined to perform this duty. Yet all people, whether they are of ordinary rank or are nobles and great individuals, ought to beware of ambition, lest, while they profess to imitate Hezekiah and David, they magnify their own name more than the name of God.