What is the source of the narration of Uthman ibn Affan letting his slave tweak his ear in retaliation, and is it authentic?

> روى أن عثمان بن عفان رضي الله عنه دَعَك أُذُن عَبْدٍ له على ذنب فعله ، ثم قال له بعد ذلك : تقدم واقرص أذني ، فامتنع العبد فألح عليه ، فبدأ يقرص بخفة ، فقال له : اقرص جيداً ، فإني لا أتحمل عذاب يوم القيامة ، فقال العبد : وكذلك يا سيدي : اليوم الذي تخشاه أنا أخشاه أيضاً > > It was narrated that ‘Uthmaan ibn ‘Affaan tweaked the ear of a slave of his when he did something wrong, then he said to him after that: Come and tweak my ear in retaliation. The slave refused but he insisted, so he started to tweak it slightly, and he said to him: Do it strongly, for I cannot bear the punishment on the Day of Resurrection. The slave said: Like that, O my master? The Day that you fear I fear also. (Islam Q&A ) Can you tell me this source of this story and if it is authentic narration?