Surah 4. An-Nisaa', Ayah 107

I.e., "you may ask God to forgive them, but do not try to find excuses for their behaviour". It is significant that the Qur'an characterizes a betrayal of trust, whether spiritual or social, as "being false to oneself" - just as it frequently describes a person who deliberately commits a sin or a wrong (zulm) as "one who sins against himself" or "wrongs himself" (zalim nafsahu)- since every deliberate act of sinning damages its author spiritually.

 lit., deceive themselves.

Our souls are a sort of trust with us. We have to guard them against all temptation. Those who surrender to crime or evil, betray that trust. We are warned against being deceived into taking their part, induced either by plausible appearances, or by such incentives to partiality as that they belong to our own people or that some link connects them with us, whereas when we are out to do justice, we must not allow any irrelevant considerations to sway us.