Sunan an-Nasa'i 14
سنن النسائي#14Sahihأَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا جَعْفَرٌ، - هُوَ ابْنُ سُلَيْمَانَ - عَنْ أَبِي عِمْرَانَ الْجَوْنِيِّ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ وَقَّتَ لَنَا رَسُولُ اللَّهِ صلى الله عليه وسلم فِي قَصِّ الشَّارِبِ وَتَقْلِيمِ الأَظْفَارِ وَحَلْقِ الْعَانَةِ وَنَتْفِ الإِبْطِ أَنْ لاَ نَتْرُكَ أَكْثَرَ مِنْ أَرْبَعِينَ يَوْمًا . وَقَالَ مَرَّةً أُخْرَى أَرْبَعِينَ لَيْلَةً .
It was narrated that Anas bin Malik said:"A time limit was set for us, by the Messenger of Allah (ﷺ), regarding trimming the mustache, clipping the nails and plucking the pubes; we were not to leave that for more than forty days," on one occasion he said: "Forty nights
Scholarly Authentication
The label above is the grade most of these scholars gave — one dissenting opinion no longer speaks for all of them. If any scholar calls a narration fabricated, that verdict is shown instead, whatever the others say. Each scholar's own wording:
In-book reference: 1:14