Musnad Ahmad 33:62

Hajjaj narrated to us, Shu'bah narrated to me, from Qatadah, who said: I heard 'Ata' ibn Abi Rabah narrating from Jabir ibn 'Abdullah, from the Prophet, may Allah bless him and grant him peace, that he said: "Al-'Umra (a gift of a house for life) is permissible."