Fiqh-us-Sunnah Volume 1, Purification and Prayer, Fiqh 1.031C.
Section : Beginning each action with the right side.
Said ‘Aishah, “The Messenger of Allah loved to begin with his right side while putting on his shoes, straightening his hair and cleaning (or purifying) himself.” (Related by al-Bukhari and Musilm.) Abu Hurairah reported that the Prophet said, “When you clothe or wash yourself, begin with your right side.” (Related by Ahmad, Abu Dawud, at-Tirmizhi, and an-Nasa’i.)