Matthew 18 verse 8. Jesus is talking about the importance of not sinning, not actually cutting your hand off.
The left hand is placed on the Bible and the right hand is raised.
When taking an oath in court on the Bible, the right hand is traditionally placed on the Bible.
The right hand typically goes on the Bible when taking an oath in court.
Typically, you place your right hand on the Bible when taking an oath in court.
Standing up with your left hand on the Bible and your right hand raised.
Although there was a Bible present, he did not place his left hand on it for some reason, perhaps religious. His right hand was raised, however.
Since oaths are sworn with the raised right hand, the left hand is the only one left to place on the Bible, thus swearing or affirming on the Bible. I think it is not so much significance of the left hand, but that the right hand is always raised for the oath - so the left is the only one left!
Traditionally, it was your right hand for cultural reasons. I do not believe that Bibles are used for this purpose any more. I personally appeared as a witness twice (in NY) and both times I was asked to swear to tell the truth. No Bible was presented and I was not asked to raise my hand.
732 times
The Bible in one hand... The gun in the other!
Matthew 6:3 But when thou doest alms, let not thy left hand know what thy right hand doeth:
Just open a Bible to the Book of Joshua, the sixth book in the Old Testament. You'll find all you want to know. (He was Moses' right-hand man, and led the Chosen People into the Promised Land after the dath of Moses.)