Musnad Abu Ya'la al-Mawsili 137:4

Al-Azraq ibn Ali narrated to us, Yahya ibn Abi Bukayr narrated to us, Bishr ibn al-Husayn al-Asbahani narrated to us, from al-Zubayr ibn Adi, from Anas, who said: The Messenger of Allah (ﷺ) said: "Let not one of you buy over the sale of his brother, and let not one of you propose over the proposal of his brother."