Ibn al-Mulaqqin reported: Al-Ahnaf ibn Qays, may Allah have mercy on him, was asked, “From whom did you learn sacred knowledge?” Al-Ahnaf said, “From myself.” It was said, “And how is that?” Al-Ahnaf said, “If I hated something did by another, I would never do the same to anyone else.”
Source: al-Tawḍīḥ li-Sharḥ al-Jāmi’ al-Ṣaḥīḥ 2/512
عن ابن الملقن عن الأحنف بن قيس رحمه الله أنه سُئِلَ ممن تعلمت العلم فقال من نفسي قيل وكيف ذلك قَالَ كنت إِذَا كرهتُ شيئًا من غيري لم أفعل باحد مثله
2/512 التوضيح لشرح الجامع الصحيح