Musnad Ahmad 788:274

'Abd al-Samad narrated to us, he said: Thabit narrated to us, he said: 'Asim narrated to us, from Abu Mijlaz, who said: Abu Musa prayed with his companions while he was traveling from Makkah to Madinah. He prayed the 'Isha' prayer as two rak'ahs and performed the taslim. Then he stood and recited one hundred verses from Surat al-Nisa' in one rak'ah. That was disapproved of by them. He said: "I have not failed to place my foot where the Messenger of Allah, peace and blessings of Allah be upon him, placed his foot, and to do as the Messenger of Allah, peace and blessings of Allah be upon him, did."