The Messenger of Allah ﷺ said, "Do not hate one another, do not turn your backs on one another, do not compete against one another, and be servants of Allah, brothers to each other."
حدثنا أبو نعيم قال حدثنا سفيان عن صالح بن نبهان
قال رسول الله ﷺ لا تباغضوا ولا تدابروا ولا تنافسوا وكونوا عباد الله إخوانا
Its isnad is sahih. It previously appeared in 7862. Bukhari related it (24/7) in the Book of Marriage, chapter "Do not propose to a woman already proposed to by your brother," and Muslim (4/1985, no. 2563) in the Book of Righteousness, chapter on the prohibition of suspicion, and Abu Dawud (4/278, no. 4910) in the Book of Manners, chapter on one who shuns his brother.