Musnad Ahmad 33:935

'Abd al-Wahhab al-Thaqafi narrated to us, from Ja'far, from his father, from Jabir, who said: "When the Messenger of Allah (ﷺ) performed ghusl (ritual bath) due to janabah (major ritual impurity), he would pour three handfuls [of water] over his head." Al-Hasan ibn Muhammad said to him: "My hair is thick." He replied: "O son of my brother, the hair of the Messenger of Allah (ﷺ) was thicker than your hair, and better."