Amir bin Abdullah bin al-Zubayr narrates from his father (Abdullah bin al-Zubayr, may Allah be pleased with them both) that when the Prophet (peace and blessings be upon him) sat in the prayer, he would place his left palm on his left thigh and his right palm on his right thigh, and point with his index finger, and his gaze (peace and blessings be upon him) would not go beyond his pointing.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2790