Musnad Ahmad 1034:137

Muhammad ibn Ja‘far narrated to us, Shu‘bah narrated to us, from Abu Ishaq, from Muslim ibn Nadhir, from Hudhayfah, who said: The Prophet, peace and blessings of Allah be upon him, took hold of the muscle of my calf—or the muscle of his calf—and said: "The right of the lower garment is up to here. If you refuse, then up to here. And if you refuse, then there is no right for the lower garment at the ankles, or there is no right for the ankles in the lower garment."