Maliks Muwatta Book 35, Hadith Number 1.

Yahya related to me from Malik from Ibn Shihab from Said ibn al-Musayyab and from Abu Salama ibn Abd ar-Rahman ibn Awf that the Messenger of Allah, may Allah bless him and grant him peace, decreed for partners the right of pre-emption in property which had not been divided up. When boundaries had been fixed between them, then there was no right of pre-emption.

Malik said, “That is the sunna about which there is no dispute among us.”