Musnad Ahmad 5:489

Waki’ narrated to us, Mujammi’ ibn Yahya narrated to us, from ‘Abdullah ibn ‘Imran al-Ansari, from ‘Ali; and al-Mas’udi, from ‘Uthman ibn ‘Abdullah ibn Hurmuz, from Nafi’ ibn Jubayr, from ‘Ali, who said: "The Messenger of Allah (may Allah bless him and grant him peace) was neither short nor tall. He had a large head and beard. He had thick palms and feet. He had large joints. His face was tinged with redness. He had a long *masrabah* (a line of hair from the chest to the navel). When he walked, he would lean forward as if he were descending from a rock. I have not seen anyone like him before him, nor after him, may Allah bless him and grant him peace." Abu al-Nadr said: "The *masrabah*." Abu Nu’aym said: "The *masrabah*," and he said: "As if he were descending from a slope." Abu Qatan said: "The *masrabah*." Yazid said: "The *masrabah*."