God places Himself into a "box". He describes in limited detail of who He is. One box He has place Himself in is Justice. He is a Just God and that Justice must be satisfied. He further narrows that box by saying that the only satisfaction is the Blood of His own Son as payment for sin and our total acceptance and reliance on that and that alone for salvation. He cannot and will not change this. If He did He would cease to be God and all life would be consumed.