This one's secular. From Bruce et al.'s wonderfully-photographed book
Keepers of the Kingdom, p. 109, describing the duties of the Gentleman Usher of the Black Rod:
During the State Opening of Parliament, which is televised every year, Black Rod can be seen walking through the Palace of Westminster to the House of Commons, where, in time-honored words, he conveys the Sovereign's command that the MPs leave the chamber and appear at the Bar of the Lords to hear the Queen's Speech. As he approaches the door, it is symbolically slammed as a reminder that the Commons fiercely guards its independence. Black Rod then gives three resounding knocks against the door with his staff of office. When it is opened, he utters the Queen's command that 'this honorable House...attend upon Her Majesty immediately in the House of Peers.'
Don't you wonder how that went over the first time it happened?