Musnad Ahmad 482:83

Al-Hakam ibn Nafi’ narrated to us, Isma’il ibn ‘Ayyash narrated to us, from Damdam ibn Zur’ah, from Shurayh ibn ‘Ubayd al-Hadrami, from someone who narrated to him, from ‘Uqbah ibn ‘Amir, that he heard the Prophet, peace and blessings of Allah be upon him, say: "Indeed, the first bone of a human being that will speak on the day when mouths are sealed is his thigh from the left leg."