The Messenger of Allah ﷺ said, "Do not envy one another, do not inflate prices against one another, do not hate one another, do not turn your backs on one another, and let none of you undercut the sale of his brother. Be servants of Allah, brothers to one another. A Muslim is the brother of another Muslim. He does not wrong him, abandon him, or look down on him. Piety is here," and he pointed to his chest three times. "It is enough evil for a man that he despises his Muslim brother. Every Muslim is sacred to another Muslim, his blood, his property, and his honor."
حدثنا عبد الرزاق حدثنا داود بن قيس عن أبي سعيد مولى عبد الله بن عامر قال سمعت
قال رسول الله ﷺ لا تحاسدوا ولا تناجشوا ولا تباغضوا ولا تدابروا ولا يبع أحدكم على بيع أخيه وكونوا عباد الله إخوانا المسلم أخو المسلم لا يظلمه ولا يخذله ولا يحقره التقوى هاهنا وأشار بيده إلى صدره ثلاث مرات حسب امرئ مسلم من الشر أن يحقر أخاه المسلم كل المسلم على المسلم حرام دمه وماله وعرضه
Its chain of transmission is sahih. Abu Saeed, the freedman of Abdullah bin Amir bin Kurayz (some say the freedman of Amir bin Kurayz), is a well known and reliable follower of the companions (tabii thiqah). Bukhari mentioned him in Kuna, no. 297, as did Ibn Abu Hatim in 4/2:376, and Ibn Hibban listed him in Thiqat. The hadith appears in Jami al-Masanid 7:445.Muslim related it in 2:279 from Abdullah bin Maslama bin Qanab, from Dawud bin Qays, with this same chain. He then related it in similar wording, with some additions and omissions, through the route of Usama bin Zayd from Abu Saeed, the freedman of Ibn Kurayz. This is hadith no. 35 of the Forty Hadith of Nawawi. Hafiz bin Rajab cited it and gave it an extensive commentary in Jami al-Ulum wal-Hikam.It will come again through the route of Dawud bin Qays at 8707, and see also 7247, 7686, 7842, 8086, 8089, 8103, 8485.