مُوَطَّأُ مَالِكٍ
Muwatta Malik 227
Jumu'a
وَحَدَّثَنِي عَنْ مَالِكٍ، عَنْ سَعِيدِ بْنِ أَبِي سَعِيدٍ الْمَقْبُرِيِّ، عَنْ أَبِي هُرَيْرَةَ، أَنَّهُ كَانَ يَقُولُ غُسْلُ يَوْمِ الْجُمُعَةِ وَاجِبٌ عَلَى كُلِّ مُحْتَلِمٍ كَغُسْلِ الْجَنَابَةِ .
Yahya related to me from Malik from Said ibn Abi Said al-Maqburi that Abu Hurayra used to say, "Doing ghusl as prescribed for major ritual impurity is incumbent (wajib) on the day of jumua on every male who has reached puberty."
Arabic/English book reference: Book 5, Hadith 2