Peace with God cost Him because only He could pay the price necessary to reconcile
Since, therefore, we have now been justified by his blood, much more shall we be saved by him from the wrath of God. For if while we were enemies we were reconciled to God by the death of his Son, much more, now that we are reconciled, shall we be saved by his life. More than that, we also rejoice in God through our Lord Jesus Christ, through whom we have now received reconciliation.
Romans 5:9-11 ESV
Jesus came to bring peace—to reconcile us to God. That’s why He came, and that’s why we celebrate His coming.