When Umar bin Khattab removed Umayr bin Saad from his post over Hims and appointed Muawiya in his place, people remarked, "He dismissed Umayr and appointed Muawiya."Umayr said, "Do not speak of Muawiya except with good, for I heard the Messenger of Allah ﷺ say, 'O Allah, guide people through him.'"
حدثنا محمد بن يحيى حدثنا عبد الله بن محمد النفيلي حدثنا عمرو بن واقد عن يونس بن حلبس
لما عزل عمر بن الخطاب عمير بن سعد عن حمص ولى معاوية فقال الناس عزل عميرا وولى معاوية فقال عمير لا تذكروا معاوية إلا بخير فإني سمعت رسول الله ﷺ يقول اللهم اهد به
No references are available.
[Hasan], but its chain of transmission is very daif, and the preceding hadith serves as a supporting witness for it.