Al-Bayhaqi reported: Abu Qilabah, may Allah have mercy on him, said, “If you hear something about your brother that you hate, then make an effort to obtain an excuse for him. If you do not find an excuse, then say to yourself: Perhaps my brother has an excuse I do not know.”
Source: Ḥilyat al-Awliyā’ 2485
عن البيهقي عَنْ أَبِي قِلابَةَ رحمه الله قَالَ إِذَا بَلَغَكَ عَنْ أَخِيكَ شَيْءٌ تَكْرَهُهُ فَالْتَمِسْ لَهُ الْعُذْرَ جَهْدَكَ فَإِنْ لَمْ تَجِدْ لَهُ عُذْرًا فَقُلْ فِي نَفْسِكَ لَعَلَّ لأَخِي عُذْرًا لا أَعْلَمُهُ
2485 حلية الأولياء لأبي نعيم عبد الله بن زيد الجرمي