"You have not heard. You have not known. Even from long ago your ear has not been open because I knew that you would deal very treacherously and you have been called a rebel from birth. For the sake of My name, I delay My wrath. And for My praise, I restrain it from you in order not to cut you off. Behold, I have refined you, but not as silver. I have tested you in the furnace of affliction. For My own sake, for My own sake, I will act. For how can My name be profaned? And My glory I will not give to another" [Is 48.8-11].
But God cannot ignore sin. It spits in the face of His goodness and makes His character as mud caked in shoe tracks. Our pride and rebellion fly in the face of His beauty and holiness. Just as He chose to restrain His wrath under the Old Covenant, He chooses to do so now as well. The reason for His restraint, however, is the same. It is the cross. For everyone who is believing, Jesus bore the wrath of God that belonged to them.
"This [the atonement] was to demonstrate His righteousness, because in the forbearance of God He passed over the sins previously committed for the demonstration of His righteousness at the present time, so that He would be just and the justifier of the one who has faith in Jesus" [Rom 3.25-26].
And lest we think that we're worth dying for, we must remember - He did this for the sake of His name. How humbling?
You know, if you're a Jew, you don't have exclamation points, bold, caps-lock, or italics. So, when you want to emphasize something, you say it twice. Like "Saul, Saul, why are you persecuting me?" in Acts 4.4. Or like Jesus' words from the cross, "My God, My God, why have you forsaken me?" in Mt 27.46. Thus, in Isaiah 48, when YHWH repeats Himself concerning His intentionality in restraining His wrath, it is most assuredly and undeniably for His great name and fame.