Each tax collector before entering on the duties of his office shall take and subscribe to the following oath in addition to the oath required of all civil officers:

"I, ______, tax collector of the County of ______, do swear that I will faithfully discharge the duties required of me by law as tax collector, and that I will diligently collect all taxes required by law for me to collect and faithfully pay these over to the persons authorized to receive the same. So help me God."