I came to Ayesha, the wife of the Prophet ﷺ, to ask her about something. She said, "Let me tell you what I heard the Messenger of Allah ﷺ say in this house of mine. He said, 'O Allah, whoever is given charge of any of my Ummah's affairs and is harsh with them, be harsh with him. And whoever is given charge of any of my Ummah's affairs and is gentle with them, be gentle with him.'"
حدثنا هارون بن معروف قال أخبرنا ابن وهب قال حدثنا حرملة
أتيت عائشة زوج النبي ﷺ أسألها عن شيء فقالت أخبرك بما سمعت من رسول الله ﷺ يقول في بيتي هذا اللهم من ولي من أمر أمتي شيئا فشق عليهم فاشقق عليه ومن ولي من أمر أمتي شيئا فرفق بهم فارفق به
Its isnad is sahih. Harmala is Ibn Imran Tujaybi, who is trustworthy and whose hadith is found in Muslim, and likewise Abdul-Rahman bin Sahammasa. The hadith was narrated by Muslim 3/1458, no. 1828, Nasai in Kubra 5/275, no. 8873, and Bayhaqi 9/43 and 10/136.