Sahih Muslim Book 3, Hadith Number 642.

Chapter : The desirability of pouring water thrice on the head and other parts (of the body).

Jabir b. ‘Abdullah reported: When the Messenger of Allah (may peace be upon him) took a bath because of sexual intercourse, he poured three handfuls of water upon his head. Hasan b. Muhammad said to him (the narrator): My hair is thick. Upon this Jabir observed. I said to him: O son of my brother, the hair of the Messenger of Allah (may peace be upon him) was thicker than your hair and these were more fine (than yours).