«كان يجعل يمينه لأكله وشربه ووضوئه وثيابه وأخذه وعطائه وشماله لما سوى ذلك»
It was the practice of the Prophet (peace and blessings be upon him):
"He (peace and blessings be upon him) would use his right hand for eating, drinking, ablution, putting on clothes, taking and giving, and his left hand for other tasks."
Hadith Referenceصحیح الجامع الصغیر / حرف الكاف / 4912