Shock & surprise – about God. Some detail to show the surprising thing in Romans 4.

Deuteronomy 25:1 describes judges: “they justify the righteous and condemn the wicked”.
In 1 Kings 8:32 Solomon prayed for God to judge just like that.

Isaiah 5:23 says, Woe to those who acquit the guilty for a bribe.

Back in Exodus 23:7 the Lord says “I will not acquit the wicked.”

Then there’s Proverbs 17:15 He who justifies the wicked and he who condemns the righteous are both alike an abomination to the LORD.

BUT Romans 4:5 calls God “him who justifies the ungodly”.
Grace & forgiveness is such a (beautiful) jolt, surprise & shock!