Dikaiosyne is the Greek word for righteousness — being right, and in right relationship, with God. It stands at the centre of Paul's gospel. The great problem of humanity is that none is righteous, no, not one; the great news is that God provides a righteousness we could never achieve, credited to those who trust Christ.
This is the heart of the good news: God made Christ, who knew no sin, to be sin for us, that we might be made the dikaiosyne of God in him. Righteousness is not first something we do but something we receive — a gift, by faith. And having received it, we are then called to live it out, hungering and thirsting after righteousness in daily life.
Dikaiosyne in Scripture
For he hath made him to be sin for us, who knew no sin; that we might be made the righteousness of God in him.