Sinodos: The Apostolic Canons (57 Canons, Fell/Schodde) 54

1A bishop or an elder or a deacon who connects himself with the army, and desires to perform these two offices, that he should follow a human calling and the priestly calling, let him be expelled. For it is said : Give unto the Lord that which is the Lord's, and unto the king that which is the king's. He who despises the king or the magistrate, except with justice, him they shall punish ; if it be one of the clergy, he shall be deposed, and if a layman, he shall be expelled.