Isaiah 36 & 37 and Isaiah 38 & 39 are bridges between the two Isaiah collections. Isaiah 1-35 are prophecies to Israel during the Assyrian period. Isaiah 40-66 are prophecies to Israel during the Babylonian period. Isaiah 36 & 37 dealt with the Assyrian attack on Israel, while Isaiah 38 & 39 deal with the healing of Hezekiah and the Babylonian delegation and the prophecy of Israel's captivity by Babylon.
In Isaiah 38, Hezekiah is sick and prays to the Lord for healing. In this prayer, he touches on repentance. There are four verses that I particularly like.
In Isaiah 38:14 Hezekiah pleads, "mine eyes fail with looking upward: O Lord, I am oppressed; undertake for me." To me this sounds like Hezekiah is having a hard time looking to the Lord … as if he is in sin (I am having a hard time praying or being faithful … looking toward heaven) He pleads to the Lord to "undertake" him. Ludlow's translation for "undertake" is "stand surety for me" while the footnote in the JST says "be my security." In both cases, it seems that Hezekiah is pleading for strength from the Lord.
In Isaiah 38:17 Hezekiah is forgiven his sins; "for peace I had great bitterness: but thou hast in love to my soul delivered it from the pit of corruption: for thou hast cast all my sins behind thy back." This reminds me of Alma the younger where he describes how he was "snatched" out of hell by the Lord (see Mosiah 27:28-29 and Alma 26:17 … also read footnote d for Mosiah 27:29 where is says HEB natzal, to snatch away from danger, to save.)
I've often wondered at what point are our sins forgiven. Is it at baptism if we are not baptized at age 8? Is it at the point where we feel Godly sorrow? I don't know why I wonder this. The point is that I can be forgiven of my sins … that Christ has provided a way. The only concern I should have is that Christ accepts my broken heart and contrite spirit. I guess when we have that "great bitterness" replaced with "peace" we know we are forgiven. When our hearts turn from stones to clay, we know we have changed to the right direction. We choose to call upon the Lord and the Lord grabs us from a course to Hell and he frankly tosses our sins behind his back. To me, that is a miracle and I stand all amazed. I wish my resolve were more sure like His.
Isaiah 38:18-19 teach us that now … today … this life is the time to repent. The grave and death cannot easily call for forgiveness. Only the living can call upon the quick and sure grasp from Hell. The Book of Mormon teaches us that we should not "procrastinate the day of [our] repentance." (Alma 34:33-35)
In Isaiah 39, the king of Babylon sends a delegation to Hezekiah congratulating him on his recovery from sickness. Hezekiah then shows this delegation all of Israel's wealth. When Isaiah hears this, he prophesies that all of these riches will be carried off and Hezekiah's posterity will become eunuchs in the palace of the king of Babylon (Isaiah 39:7). To this prophesy Hezekiah responds, "Good is the word of the Lord … there shall be peace and truth in my days" (Isaiah 38:8) as if to say, "boy that sounds bad for my kids and grandkids … I'm glad it's not going to happen while I'm alive."
Although each of us is responsible for our own actions, we still will be held accountable for our children. If we don't do our part to help the next generation, the natural consequences are easily seen. Each generation builds on the previous generation. If we don't establish a base upon which the next generation can build, then what good are we doing? Each of us must be a strong link in the eternal chain of families.