It was narrated that Abu Hurairah said:"The Messenger of Allah said: 'When anyone of you cleans himself, he should not clean himself with his right hand. Let him clean himself with his left hand.'"
حَدَّثَنَا يَعْقُوبُ بْنُ حُمَيْدِ بْنِ كَاسِبٍ، حَدَّثَنَا الْمُغِيرَةُ بْنُ عَبْدِ الرَّحْمَنِ، وَعَبْدُ اللَّهِ بْنُ رَجَاءٍ الْمَكِّيُّ، عَنْ مُحَمَّدِ بْنِ عَجْلاَنَ، عَنِ الْقَعْقَاعِ بْنِ حَكِيمٍ، عَنْ أَبِي صَالِحٍ، عَنْ أَبِي هُرَيْرَةَ، قَالَ قَالَ رَسُولُ اللَّهِ ـ صلى الله عليه وسلم ـ " إِذَا اسْتَطَابَ أَحَدُكُمْ فَلاَ يَسْتَطِبْ بِيَمِينِهِ لِيَسْتَنْجِ بِشِمَالِهِ " .
IbnMaja
The Book of Purification and its Sunnah • Hadith 312