expression
condemn the offense, but not the offender
Proverb advising to separate the wrong act from the person who committed it; hate the sin, not the sinner.
See also: その罪を憎んでその人を憎まず
罪を憎んで人を憎まずという言葉があるように、彼のしたことは許せなくても、彼自身を憎んではいけない。
As the saying goes, 'condemn the offense, but not the offender'; even if you can't forgive what he did, you shouldn't hate him as a person.
A Japanese proverb likely derived from Christian or Buddhist teachings emphasizing compassion and separation of act from actor. The exact origin is uncertain.