Rashi on the Former Prophets

In those days. [This occurred] three days before Sancheiriv's downfall.
Chizkiyohu became … ill. On the third day, when he went up to the Beis [Hamikdosh] of A, was the day of Sancheiriv's downfall, and it was on the Pesach holiday.
For you are going to die. On this world.
And you will not live. In the World to Come because you have not married as is [explained] in [Maseches] Berachos.

Had not gone out of the … courtyard, etc. The Holy One, Blessed Is He, hurried to notify him about his cure before the rumor would spread in the city that he has been sentenced to death, as stated in [Talmud] Yerushalmi.

And I will save you from the hand of the king of Ashur. We learn that he became ill before Sancheiriv's downfall.

A cake of pressed figs. When they are fresh, they are called תאנים [=figs], and when they are pressed into a round cake, they are called דבלה.
And placed it on the boil, and it was healed. This was a miracle within a miracle, for even healthy flesh, when you place a cake of pressed figs upon it, decays, yet the Holy One, Blessed Is He, [instructs to] put something that is injurious upon something that is vulnerable, and it becomes healed.

Should the shade advance ten steps or should it go back ten steps? This is an abbreviated verse. The shade had already advanced the steps that are made [to measure] the hours of the day, like, oriloje, in O. F., the clocks that people make to determine the hour of the day. [He asked,] “Do you wish it to stay in the place where it is, for as long as it takes it to walk in ten hours, or should it go back up ten steps so that it will appear as though it is morning?”

And Chizkiyohu said, ”It is easier for the shade to advance ten steps.” It is easy [for the shade] to remain in its place, and stay for ten steps, it is not something that is so conspicuous. Not so, rather let the shade go back, and the event will be a wonder, for they saw that the day was turning toward evening, and it returns to become morning [again].

That it had gone down on the steps of Achaz. The day that Achaz died, the day was shortened, and the shade hurried to advance ten steps, so that he would not be eulogized, and those ten hours returned now for Chizkiyohu.

For he heard that Chizkiyohu was ill. And until that day no person who had ever been ill, had become well. Now, how did he hear? He was accustomed to eat after three hours [had elapsed] in the day, and he would sleep until the ninth [hour of the day]. Because the cycle of the sun had gone backwards on account of Chizkiyohu, he awoke after nine hours [of the day] and found that it was morning, and he wanted to kill his servants. He said, ”You let me sleep a day and a night!” They replied, “The sun's cycle went backwards.” He asked them, “Who brought it back?” They said to him, “The God of Chizkiyohu,” as is [stated] in Pesikta.

His treasure house. The storehouse of his spices, as in, “spices [=נכאת], balm, and lotus.”
The fine oil. Some interpret this as the anointment oil, and others interpret it as balsam oil, which is found in Eretz Yisroel, as it is said, ”Yehudah and [Eretz] Yisroel, they were your merchants, with wheat of מנית and פנג,” and I saw in the book of Yosephun, that פנג is balsam, and it grows in Yericho, and because of its aroma [=ריח], it is called Yericho [=יריחו].
There was nothing. [He even showed them] the Ark, the Luchos, and the Torah Scroll.

”They came from a distant land.” This is one of the three [men] whom the Holy One, Blessed Is He, tested and found them to be a pot of muddy water: [The three are,] Kayin, Chizkiyohu and Bilam. Kayin [said], “I don't know, am I my brother's keeper?” He should have said, ”Master of the Universe are all hidden things not revealed to You?” as it is [stated] in [Midrash] Tanchuma. Bilam, when the Omnipresent said to him, ”Who are these men with you?” he should have said, “Adonoy God, You know!” as it is stated concerning Yechezkeil, but he replied arrogantly, ”Balak son of Tzippor, king of Moav, sent them to me,” [i.e.,] many people seek me. Chizkiyohu should have replied to Yeshayohu, ”You are the prophet of the Omnipresent, yet you are asking me?” [Instead,] Chizkiyohu began to become haughty, and said, ”They came to me from a distant land.” Therefore, he was punished, and also [he was punished] because he rejoiced over them, and served them at his table.

Nothing will remain. You shall be paid measure for measure, [as stated above,] “There was nothing.”

And some of your sons. Chananyoh, Mishoeil, and Azaryoh.

”The word of Adonoy … is good.” Because in my days there will be peace.

And how he made the pool, etc. In Divrei Hayomim.