Musannaf Ibn Abi Shayba 9:1164

'Abdah narrated to us, from 'Abd al-'Aziz ibn 'Umar, from al-Rabi' ibn Sabrah, from his father, who said: I saw the Messenger of Allah (may Allah bless him and grant him peace) standing between the Corner and the Door, and he was saying: "O people, I had permitted you the *istimta'* (temporary marriage). Behold, Allah has forbidden it until the Day of Resurrection. So whoever has anything of them (women in such marriages), let him let her go, and do not take back anything of what you have given them."