Albert Barnes Commentary 2 Kings 20:1

"In those days was Hezekiah sick unto death. And Isaiah the prophet the son of Amoz came to him, and said unto him, Thus saith Jehovah, Set thy house in order: for thou shalt die, and not live." — 2 Kings 20:1 (ASV)

In those days — Hezekiah seems to have died in 697 B.C., and his illness must belong to 713 or 714 B.C. (compare 2 Kings 20:6), a date that falls early in the reign of Sargon. The true chronological place of this narrative is therefore before all the other events recorded of Hezekiah, except for his religious reforms.

The prophet Isaiah the son of Amoz — This full description of Isaiah (compare 2 Kings 19:2), which includes his father’s name and his office, marks the original independence of this narrative. The author of Kings may have found it completely separate from the other records of Hezekiah and added it in the state in which he found it.

This history shows that prophetic denunciations were often not absolute predictions of what was certain to happen. They were primarily designed to test or lead to repentance those against whom they were uttered, and were fulfilled only if this primary design failed.