When the Bible talks about Christians being the righteousness of God in Christ in 1 Corinthians 5:21, it means they have a rightness from God. It’s a quality of being right or righting wrongs.
By righting wrongs, it doesn’t mean poking noses in other people’s business and being sanctimonious, no. Righteousness means that when things go wrong in the lives of Christians as they often do, this quality of excellence from God acts as a reset mechanism. If they are sick, healing resurges. If they incur debts, ideas of how to repay the debt float up in their minds.
It’s a quality that so many Christians have but never acknowledge. So the next time you encounter the word, ‘righteousness’ in the Biblical context, this is the quality being described.