Musnad Abu Ya'la al-Mawsili 244:15

Dawud ibn Rashid narrated to us, Walid ibn Muslim narrated to us, from Ibn al-Ahnaf, who heard Abu Salam al-Aswad say: Abu Salih al-Ash'ari informed me that Abu Abdullah al-Ash'ari narrated to him that the Messenger of Allah (may Allah bless him and grant him peace) saw a man who was not completing his bowing (ruku') nor his prostration (sujud). He said: "If this man were to die while he is in this state, he would die upon other than the religion of Muhammad (may Allah bless him and grant him peace). So complete the bowing and the prostration, for the likeness of the one who prays and does not complete his bowing and his prostration is like the hungry person who eats nothing but a date or two dates; they do not avail him of anything." Abu Salih said: So I met Abu Abdullah and said: "Who narrated this hadith to you, that he heard it from the Messenger of Allah (may Allah bless him and grant him peace)?" He said: "The commanders of the armies narrated it to me: Khalid ibn al-Walid, Shurahbil ibn Hasana, and Amr ibn al-As, that they heard it from the Messenger of Allah (may Allah bless him and grant him peace)."