Sinodos: The Apostolic Canons 11

1It is not allowed to a bishop to leave his diocese and be ordained over another, even if the people should urge him, except for the sake of benefit, and [unless] they shall urge him to do this, because he will be able to benefit those who are there through the word of truth. But this he shall not do of his own account, but according to the judgment of many bishops and on account of a very strong entreating.