Musannaf Ibn Abi Shaybah

Hazrat Jabir bin Samurah narrates that the hair on the front part of the head and beard of the Messenger of Allah (peace be upon him) had turned white. When he applied oil and then combed them, they would not be visible, and his beard was very thick. A man asked, "Was your face like a sword?" He replied, "No, rather it was round like the sun and the moon." And I saw the Seal of Prophethood between his shoulders, which was like the size of a pigeon’s egg and resembled his body.