I adore the book of Isaiah!  It has so much to absorb in it! 

And if you leave God's path and go astray, you will hear a voice behind you say, "No, this is the way;walk here." Isaiah 30:21

"I, yes, I alone am He who blots away your sins for my own sake and will not think of them again."  Isaiah 43:25

Isaiah the Prophet in the old Testiment, was one of Jesus' favorite books.  He quoted from it frequently because the central theme is salvation.
"I have blotted out your sins; they are gone like morning mist at noon!  Oh, return to me, for I have paid the price to set you free." Isaiah 44:22

"Come, let's talk this over! Says the Lord; no matter how deep the stains of your sins, I can take it out and make you as clean as fresh fallen snow.  Even if you are stained as red as crimson, I can make you white as wool."  Isaiah 1:18