Therefore, having been justified by faith, we have peace with God through our Lord Jesus Christ. Rom 5:1
As sinners, we have "no works of righteousness" and we were in a state of "enmity with GOD". CHRIST being righteous, has done great sacrifice for us on the cross to be justified with GOD. Now by believing in HIM, we have inherited the "RIGHTEOUSNESS of GOD".
CHRIST being a peace-maker, became mediator to establish peace between GOD and HIS children. Now being reconciled, we have "PEACE with GOD". FAITH in CHRIST is the one and only gracious way to be united with HIM, justified and accepted before GOD.