Ibn al-Qayyim: if they seek your pardon...

Ibn al-Qayyim (Allah have mercy on him): 

If someone has wronged you and they seek your pardon, it is from humility (to Allah) that is necessitates accepting their excuses, whether they are speaking the truth or not - and for you to leave their affair with Allah.

Madaarij as-Saalikeen, 2/337