Sahih al-Bukhari 5380

ʿAbdan narrated to us: ʿAbdullah informed us: Shuʿbah informed us, from Ashʿath, from his father, from Masruq, from ʿAʾishah, may God be pleased with her, who said: “The Prophet, peace and blessings be upon him, liked to begin with the right side whenever possible in his purification, putting on his sandals, and combing his hair.” Before this, at Wasit, he had said that this applied to all his affairs.