Musnad Ahmad 513:1

Muhammad ibn Bakr and Abd al-Razzaq narrated to us, they said: Ibn Jurayj informed us, Uthman ibn Abi Sulayman informed me, from Ibn Mas'adah, the commander of the army, he said: I heard the Prophet, peace and blessings of Allah be upon him, saying: "I have become heavy (in body), so whoever misses my bowing, let him catch it during my slow rising." And Abd al-Razzaq said: "During my slow rising."