Musnad Ahmad 334:6

Muhammad ibn Ja‘far narrated to us, he said: Shu‘bah narrated to us, from ‘Amr ibn Dinar, he said: I heard al-Hasan ibn Muhammad narrating from Jabir ibn ‘Abd Allah and Salamah ibn al-Akwa‘, they both said: "The herald of the Messenger of Allah (may Allah bless him and grant him peace) came out to us and called out: 'The Messenger of Allah has given you permission, so enjoy yourselves (mut‘ah),' meaning: temporary marriage with women."