Sahih Muslim Book 10, Hadith Number 3916

Jabir bin ‘Abdullah (Allah be pleased with them) said that the Messenger of Allah (may peace be upon him) decreed pre-emption in every joint ownership and not divided-the one-it may be a dwelling or a garden. It is not lawful for him (for the partner) to sell that until his partner gives his consent. He (the partner) is entitled to buy it when he desires and he can abandon it if he so likes. And if he (the one partner) sells it without getting the consent of the (other partner), he has the greatest right to it.