Genesis 41:14

‘Then Pharaoh sent and called Joseph, and they brought him hastily out of the prison, and he shaved himself and changed his clothing and came in to Pharaoh's presence.'

Egyptian custom demanded that a man be specially prepared before he was brought before Pharaoh. Access to Pharaoh was limited, and to approach him, for he was seen as a god, was both a unique privilege and a dangerous thing, and required ritual cleanness. It is constantly apparent that the writer takes the Egyptian background in his stride in all sorts of ways (as well as the Canaanite background, as we shall see later) strengthening the view that this is written by someone familiar with the events and their background.