Musnad Ahmad 830:87

'Ali ibn 'Abdullah narrated to us, Mu'adh ibn Mu'adh narrated to us, Shu'bah narrated to us, Fudayl ibn Fadalah narrated to me, he said: 'Abd al-Rahman ibn Abi Bakrah narrated to me, he said: Abu Bakrah saw people praying the Duha (forenoon) prayer, so he said: "They are indeed praying a prayer that the Messenger of Allah, peace and blessings of Allah be upon him, did not pray, nor did the generality of his companions."