Sahih al-Bukhari 5380
Sahih al-Bukhari · Book 70: Food, Meals · To eat with right hand, and to start with the right side in doing other things.
Narrated `Aisha:
حَدَّثَنَا عَبْدَانُ ، أَخْبَرَنَا عَبْدُ اللَّهِ ، أَخْبَرَنَا شُعْبَةُ ، عَنْ أَشْعَثَ ، عَنْ أَبِيهِ ، عَنْ مَسْرُوقٍ ، عَنْ عَائِشَةَ ـ رضى الله عنها ـ قَالَتْ كَانَ النَّبِيُّ صلى الله عليه وسلم يُحِبُّ التَّيَمُّنَ مَا اسْتَطَاعَ فِي طُهُورِهِ وَتَنَعُّلِهِ وَتَرَجُّلِهِ. وَكَانَ قَالَ بِوَاسِطٍ قَبْلَ هَذَا فِي شَأْنِهِ كُلِّهِ.
The Prophet (ﷺ) used to love to start doing things from the right side whenever possible, in performing ablution, putting on his shoes, and combing his hair. (Al-Ash'ath said: The Prophet (ﷺ) used to do so in all his affairs.)