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."

أَخْبَرَنَا قُتَيْبَةُ، قَالَ حَدَّثَنَا جَعْفَرٌ، - هُوَ ابْنُ سُلَيْمَانَ - عَنْ أَبِي عِمْرَانَ الْجَوْنِيِّ، عَنْ أَنَسِ بْنِ مَالِكٍ، قَالَ وَقَّتَ لَنَا رَسُولُ اللَّهِ ﷺ فِي قَصِّ الشَّارِبِ وَتَقْلِيمِ الأَظْفَارِ وَحَلْقِ الْعَانَةِ وَنَتْفِ الإِبْطِ أَنْ لاَ نَتْرُكَ أَكْثَرَ مِنْ أَرْبَعِينَ يَوْمًا . وَقَالَ مَرَّةً أُخْرَى أَرْبَعِينَ لَيْلَةً .