Musnad Ahmad 30:548

'Abd al-Razzaq narrated to us, Ma'mar narrated to us, from al-Zuhri, from Abu Salamah ibn 'Abd al-Rahman and Abu Bakr ibn Sulayman ibn Abi Hathmah, from Abu Hurayrah, who said: The Messenger of Allah (peace and blessings of Allah be upon him) prayed Dhuhr or 'Asr, and he performed the taslim after two rak'ahs. Dhu al-Shimlayn ibn 'Abd 'Amr—who was an ally of Banu Zuhrah—said to him: "Has the prayer been shortened, or have you forgotten?" The Prophet (peace and blessings of Allah be upon him) said: "What is Dhu al-Yadayn saying?" They said: "He has spoken the truth, O Prophet of Allah." So he completed for them the two rak'ahs that were missing.