The McTavish carpenter shop is always portrayed to be on the ground floor, but at the end, when John reads the bible to Mary, the view from the window behind them shows an overhead view of the city.
At the time this movie was made, affinity laws prevented a person from marrying his brother's widow.
A title card purports to identify Aaron, the brother of Moses, but the actor shown is the one playing Moses.
When God gives the commandments through the eruption of Sinai, it's clear that the explosion graphics are being played backwards.
While lying in the wrecked cathedral, dying, Mother McTavish moves her head, and her hair does not move with it as it should. She is clearly wearing a wig.
When the Red Sea is parted, it's clear that the water is running over a solid, downward-curved surface.
As the Pharaoh and his henchmen pursue the Hebrews at the Red Sea, several of the chariots obviously crash. (These were accidents which occurred while filming because the chariots were difficult to drive.)
When the Red Sea is parting, it's clear that the filmed footage was played in reverse.
The type of staff used by Moses and his followers has a Star of David on the end. The Star of David didn't become a symbol of Judaism until the Middle Ages.