why it's GOOD news.

"The background of the good news of the gospel is the bad news about the sinfulness of sin and the certainty of sin's judgment...

Sin is essentially the resolve - the mad, utterly blameworthy, but nonetheless, utterly firm resolve - to play God and fight the real God. Sinners resolve to treat themselves as the center of the universe and so they keep God at bay on the outer circumference of their lives - or so they think. They won't allow the Creator to rule over them as he wills to do. If they appeal to God at all, they ask God to act according to their will and for their convenience like a servant who gets them out of trouble and bestows on them good gifts. They never serve him from the heart and only resent the claim to dominion that he makes... sin wills the fundamental abolition of God. Sin wills that God should not be there. Sin plays God, sin fights God, and sin wishes that God didn't exist at all...

God cannot help recoiling from that attitude in man that expresses itself in fighting him, defying him, and willing him out of existence. You cannot wonder that he hates the abominations which sin produces. God is holy. Sin is uncleanness in his eyes and he hates it... God is just. This means God does everything right and deals rightly with everyone. God expresses his justice by dealing with sin as sin ought to be dealt with... The just God will deal with sin as sin deserves..."

j.i. packer

as part of the answer to the question of "whether or not the atonement (at the cost of His Son) was necessary" in the book atonement