Musannaf Ibn Abi Shaybah

Hazrat Abdullah bin Zubair narrates that when the Holy Prophet (peace and blessings be upon him) would sit in the Qa'dah, he would place his right hand on his right thigh and supplicate, and place his left hand on his left thigh. He would gesture with his index finger and place his thumb on his middle finger, and would keep his left palm resting on his knee.