Musannaf Ibn Abi Shaybah

It is narrated from Hazrat Muhammad bin Yahya bin Haban that the Messenger of Allah, peace and blessings be upon him, said: Because of the increase in my age, flesh has increased on my body. Do not go ahead of me in bowing (ruku) and prostration (sajdah). When going into ruku, I may go ahead of you, but when rising from ruku, you will catch up with me. When going into sajdah, I may go ahead of you, but when rising from sajdah, you will catch up with me.