From here

I just wanted to share something that I thought was pretty cool. Yesterday we went to my parents’ ward and President Oaks was there for his great-grandson’s baby blessing. President Oaks came to elder’s quorum and shared a message about the sacrament. He stressed that it is a sacred ordinance and that it is important to take the sacrament with the right hand. I never knew that the hand that we took it with was important, but he compared it to raising the right hand to the square when we perform a baptism - if we raised the left hand it would be wrong. It’s something very simple, but there is power in exact obedience to what the Lord commands. I know that God has called prophets and apostles to guide us!