Musnad Ahmad 648:12

Aswad ibn Amir narrated to us, Sharik narrated to us, from Abu Hashim, from Abu Mijlaz, who said: Ammar performed a prayer and made it brief. He was asked, or it was said to him [about it], so he said: "I did not deviate from the prayer of the Messenger of Allah, may Allah bless him and grant him peace."