Instead we should be asking, "How can God be completely holy and completely just, and yet forgive us and show mercy to us when we rebel against Him? How can God satisfy His character and save our souls at the same time?"
The Gospel is the answer. It's only by His blood. His blood covers us. His wrath is satisfied on the cross. Look at the cross. This is the beauty of the Gospel. See the beauty of the cross?
Praise God from whom all blessings flow! He is merciful towards us as sinners - He substitutes Himself in our place!