It was narrated that Anas bin Malik said:"We were given a time limit with regard to trimming the mustache, shaving the pubic hairs, plucking the armpit hairs and clipping the nails. We were not to leave that for more than forty days
Hadith No. 295
Sunan Ibn Majah
Gradings:
Al-Albani:
Sahih
Muhammad Fouad Abd al-Baqi:
Sahih
Zubair Ali Zai:
Sahih Muslim