Musannaf Ibn Abi Shayba 3:2121

Shababa narrated to us, he said: Layth ibn Sa'd narrated to us, from Yazid, that Abd al-Rahman ibn Shamasa narrated to him that Uqbah ibn Amir stood up during a prayer while he was sitting. The people said, "Subhan Allah," so he understood what they wanted. When he finished the prayer, he performed two prostrations while he was sitting, then he said, "I have heard what you said, and this is the Sunnah."