Musnad Abu Ya'la al-Mawsili 42:311

Abu Khaythama narrated to us, Ismail bin Ulayyah narrated to us, from Ali bin al-Mubarak, Yahya bin Abi Kathir narrated to us, Abu Sa’id, the freed slave of al-Mahri, narrated to me, from Abu Sa’id al-Khudri: That the Messenger of Allah (may Allah bless him and grant him peace) sent an expedition to Banu Lihyan of Hudhayl. He said: "Let one man from every two men go forth, and the reward shall be between them." And the Messenger of Allah (may Allah bless him and grant him peace) said: "O Allah, bless for us our sa’ and our mudd, and make with the blessing two blessings."