Musannaf Ibn Abi Shayba 3:5829

Jarir narrated to us, from Mansur, from Abu Wa'il, from Masruq, who said: I stayed with him for two years, and he would pray two rak'ahs at as-Silsilah. He said: So I said to him, "What prompted you to do this, O Abu 'A'ishah?" He replied, "Seeking the Sunnah."