Righteousness
is,
The perfection and holiness of God.
Also,
purity of heart; moral goodness of behavior; heart and life being in obedience to God's laws.

"[Righteousness] includes all we call
justice, honesty, and virtue,
with holy affections;
in short, it is true religion."
Noah Webster's
1828

Be ye not unequally yoked together
with unbelievers:
for what fellowship hath
righteousness with unrighteousness?
and what communion
hath light with darkness?

2 Corinthians 6:14

In the verse below, 'the righteous' refers to those who are perfect and holy in God; those who have goodness of behavior, and heart and life in oobedience to God's laws.
...I did not come to call the righteous, but sinners to repentance...

In the verse below, 'the righteous' refers to those who are perfect and holy in God; those whose hearts and lives are in obedience to God's laws; those who are just, honest, and virtuous....

" I did not come to call the righteous,
but sinners to repentance..."
Matthew 9:13