Sahih al-Bukhari 882
Narrated Abu Huraira:
While `Umar (bin Al-Khattab) was delivering the Khutba on a Friday, a man entered (the mosque). 
`Umar asked him, "What has detained you from the prayer?" The man said, "It was only that when I 
heard the Adhan I performed ablution (for the prayer)." On that `Umar said, "Did you not hear the 
Prophet saying: 'Anyone of you going out for the Jumua prayer should take a bath'?".
حَدَّثَنَا أَبُو نُعَيْمٍ، قَالَ حَدَّثَنَا شَيْبَانُ، عَنْ يَحْيَى، عَنْ أَبِي سَلَمَةَ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ عُمَرَ ـ رضى الله عنه ـ بَيْنَمَا هُوَ يَخْطُبُ يَوْمَ الْجُمُعَةِ إِذْ دَخَلَ رَجُلٌ فَقَالَ عُمَرُ لِمَ تَحْتَبِسُونَ عَنِ الصَّلاَةِ فَقَالَ الرَّجُلُ مَا هُوَ إِلاَّ سَمِعْتُ النِّدَاءَ تَوَضَّأْتُ‏.‏ فَقَالَ أَلَمْ تَسْمَعُوا النَّبِيَّ صلى الله عليه وسلم قَالَ ‏
"‏ إِذَا رَاحَ أَحَدُكُمْ إِلَى الْجُمُعَةِ فَلْيَغْتَسِلْ ‏"‏‏.‏