Prophet Mohammad (PBUH)‏

اطْلُبْ لِأَخِيكَ عُذْراً فَإِنْ لَمْ تَجِدْ لَهُ عُذْراً فَالْتَمِسْ لَهُ عُذْراً.

Make an excuse for your fellow brother, and even if you do not have an excuse [for his behaviour], then seek out an excuse for him.

Bihar al-Anwar, vol. 72, pg. 197