كتاب الجمعة
7  
The Book of Prayer - Friday
(1)
Chapter: Ghusl on Friday is obligatory for all adult men, and clarifying what they were ordered regarding it
(1)
باب وُجُوبِ غُسْلِ الْجُمُعَةِ عَلَى كُلِّ بَالِغٍ مِنَ الرِّجَالِ وَبَيَانِ مَا أُمِرُوا بِهِ ‏
Sahih Muslim 847 b

'Aisha reported:

The people (mostly) were workers and they had no servants. Ill-smell thus emitted out of them. It was said to them: Were you to take bath on Friday.
وَحَدَّثَنَا مُحَمَّدُ بْنُ رُمْحٍ، أَخْبَرَنَا اللَّيْثُ، عَنْ يَحْيَى بْنِ سَعِيدٍ، عَنْ عَمْرَةَ، عَنْ عَائِشَةَ، أَنَّهَا قَالَتْ كَانَ النَّاسُ أَهْلَ عَمَلٍ وَلَمْ يَكُنْ لَهُمْ كُفَاةٌ فَكَانُوا يَكُونُ لَهُمْ تَفَلٌ فَقِيلَ لَهُمْ لَوِ اغْتَسَلْتُمْ يَوْمَ الْجُمُعَةِ ‏.‏
Reference : Sahih Muslim 847b
In-book reference : Book 7, Hadith 9
USC-MSA web (English) reference : Book 4, Hadith 1840
  (deprecated numbering scheme)