Those for whom Christ obeyed for, and made righteous by His one obedience as Per Rom 5:19
19 For as by one man's disobedience many were made sinners,
so by the obedience of one shall many be made righteous.
They are the ones who keep the commandments of God, by Christs One obedience,
The word for righteous in Rom 5:19 is the greek word δίκαιος:
righteous, observing divine laws
- in a wide sense, upright, righteous, virtuous, keeping the commands of God
- innocent, faultless, guiltless
- used of him whose way of thinking, feeling, and acting is wholly conformed to the will of God, and who therefore needs no rectification in the heart or life
So those ones receive a Gift of Righteousness, which includes having kept the commandments of God, in courtesy of Jesus Christ who kept the commandments of God for them.
So Rom 5:19 teaches that Christs One Obedience effects the full salvation of the many, without their obedience, because its effected by the Obedience of Just One, Jesus Christ,
If you dont believe this, you are in unbelief !