Sunan Abi Dawud Book 35, Hadith 42
The Messenger of Allah (ﷺ) fixed forty days to shave the pubes, paring the nails, clipping the moustaches, and plucking the hair under the armpit.
Abu Dawud said: Ja'far b. Sulaiman transmitted it from Abu 'Imran on the authority of Anas. In this version he did not mention the Prophet (ﷺ). He said: Forty days were fixed for us. This is a more correct version.