Al-Bukhari reported: Ibn Abbas, may Allah be pleased with him, said, “If you intend to mention the faults of your companions, then remember your own faults.”
Source: al-Adab al-Mufrad 328
Grade: Hasan (fair) according to Al-Bukhari
Ibn Qudamah said, “Beware of being preoccupied with rectifying others before you rectify yourself. Busy yourself with rectifying your heart within you and purifying it from blameworthy traits such as greed, envy, ostentation, and vanity before rectifying what is outside of you.”
Source: Mukhtaṣar Minhāj al-Qāṣidīn 1/20
عن البخاري وقال بن عباس رضي الله عنه إِذَا أَرَدْتَ أَنْ تَذْكُرَ عُيُوبَ صَاحِبِكَ فَاذْكُرْ عُيُوبَ نَفْسِكَ
328 الأدب المفرد للبخاري
قال ابن قدامة وإياك أن تشتغل بما يصلح غيرك قبل إصلاح نفسك واشتعل بإصلاح باطنك وتطهيره من الصفات الذميمة كالحرص والحسد والرياء والعجب قبل إصلاح ظاهرك
1/20 مختصر منهاج القاصدين