It is narrated from Sayyiduna Ibn Mas'ud (may Allah be pleased with him) that the Prophet (peace and blessings of Allah be upon him) said the takbeer while teaching us the prayer and raised his hands, then when he bowed (in ruku'), he placed his hands together between his knees. When Sayyiduna Sa'd (may Allah be pleased with him) learned of this, he said, "My brother has spoken the truth. We used to do it this way at first, but later we were commanded to hold the knees."