Rashi on TanakhIsaiah 39

when he heard that he had been ill and had recovered He was accustomed to eating after the first three hours of the day had elapsed and he would sleep until the ninth hour. Since the sphere of the sun had gone backwards because of Hezekiah, he awoke from his sleep after nine hours and found that it was morning. He sought to kill all his servants. He said, “You let me sleep a day and a night until morning!” They said to him, “It was the sphere of the sun that went backwards.” He said to them, “Who brought it back?” They said to him, “The God of Hezekiah, etc.” As is stated in Tanhuma (Ki Thissa 5) and in Pesikta (d’ Rav Kahana p. 14a).

his entire treasure house (נְכֹתֹה) the storehouse of his spices, like (Gen. 37:25) “spices (נְכֹאת), balm, and lotus.”

and the good oil Some interpret this as the anointing oil (Ex. 30:22 33), and others say that it is balsam oil, which is found in Eretz Israel, and that is Pannag mentioned in Ezekiel (27:17): “Judah and the land of Israel, they were your merchants, with wheat of Minnith and Pannag.” I saw in the book of Josephon (book 4, ch. 22), Pannag is balsam, and it grows in Jericho. Therefore, it is called Jericho because of the aroma (רֵיחַ).

there was nothing Even the Scroll of the Law.

“They have come to me from a distant country” This is one of three people whom the Holy One, blessed be He, tested and found to be a chamber pot: Cain, Hezekiah, and Balaam. Hezekiah should have replied, “You are a prophet of the Omnipresent. Yet you ask me?” Instead, he commenced to become haughty, and said, “They have come to me from a distant country.” Therefore, he was punished, and because he rejoiced over them and fed them on his table. Similarly, Balaam, to whom He said, “Who are these men with you?” (Num 22:9) And he replied and said, “Balak the son of Zippor sent them to me.” Similarly, Cain, to whom He said, “Where is your brother Abel?” (Gen. 4:9) He should have replied, “Lord of the Universe, are not all hidden things revealed to You?” As it is stated in Tanhuma.

nothing shall remain You shall be paid in kind, corresponding to “There was nothing (v. 4).” (I.e., Hezekiah would be punished for showing off all his treasures, by having all those treasures carried off to Babylonia.)

And...[some] of your sons Hananiah, Mishael, and Azariah.

“The word of the Lord...is good” since there will be peace in my days.