'Right hand' in the Bible

Then Joseph took them both—with his right hand Ephraim toward Israel’s left, and with his left hand Manasseh toward Israel’s right—and brought them to Israel.

But Israel stretched out his right hand and put it on the head of Ephraim, the younger, and crossing his hands, put his left on Manasseh’s head, although Manasseh was the firstborn.

When Joseph saw that his father had placed his right hand on Ephraim’s head, he thought it was a mistake and took his father’s hand to move it from Ephraim’s head to Manasseh’s.

Joseph said to his father, “Not that way, my father! This one is the firstborn. Put your right hand on his head.”