Many centuries before Jesus came and God offered us the New Covenant with Jesus, it was prophetically announced in the Psalms that God’s grace, which we did not deserve, will reconcile us to God:
“The Lord is compassionate and gracious, slow to anger, abounding in love. He will not always accuse, nor will he harbor his anger forever; he does not treat us as our sins deserve or repay us according to our iniquities.” (Psalm 103:8-10; NIV)
It’s wonderful that God doesn’t judge us by what we do, but that He looks at what Jesus did (which is that He took all of our punishment). We don’t get what we deserve for our sins. Because we all of us — without exception — fail and would never be able to live together with our perfect Creator, if it wasn’t for Jesus’ sacrifice for us.