It is narrated from Abbas bin Sahl: Muhammad bin Maslamah, Abu Humayd, Abu Usayd and Sahl bin Sa'd (may Allah be pleased with them) gathered and spoke about the prayer of the Messenger of Allah (peace and blessings be upon him). Sayyiduna Abu Humayd (may Allah be pleased with him) said: I know the prayer of the Messenger of Allah (peace and blessings be upon him) better than all of you. The Messenger of Allah (peace and blessings be upon him) stood, said the takbir and raised both hands. Then he raised both hands when he said the takbir for the bowing. Then he bowed and placed his hands on his knees as though he were gripping them, and he held his arms taut like a bowstring, keeping them away from his sides, and he neither lowered his head nor raised it. Then he raised both hands and stood up straight until every bone settled in its place. Then he prostrated, placing his forehead and nose firmly on the ground, keeping his hands away from his sides and placing his palms level with his shoulders, until he finished. Then he sat, spreading out his left foot and turning the front of his right foot toward his qiblah, placed his left hand on his left knee and his right hand on his right knee, and pointed with his finger.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الصلاة / 2518