Father McAllister's Hairshirt

Did anyone notice, as Father McAllister was getting undressed and getting ready to go to bed, he was wearing a burlap hairshirt under his clothes. This goes back to medieval times, and was worn as an undergarment by the clergy as a form of repentance and humility. It was meant to irritate the skin, it was very scratchy and prickly, and was a way of doing penance for one's sins.