Righteousness does not consist in correct behavior but in genuine co-suffering love…No deed has any moral value unless it proceeds from the heart motivated by love. Otherwise it is simply ethical or correct behavior according to one or another system of laws, a human work which anyone in any culture with or without faith in God can attain to.
The Old Testament Law could help to preserve society but it could not save anyone, no matter how diligently they fulfilled it to the letter. Moreover, since it could not transform the heart, it could not even preserve the nation from falling constantly away from God. Our Lord Jesus Christ, the only one who fulfilled righteousness was motivated solely by love, co-suffering love.
And this is why our Lord Jesus Christ became our righteousness on the cross and imputed that righteousness to us through faith.
(Lazar Puhalo, For a Culture of Co-Suffering Love, p. 14)