Before entering on the duties of their offices, the judges of the probate courts must take and file the oaths required of all civil officers and, in addition, the following oath:

"I do swear that I will well and faithfully discharge the duties of judge of the probate court for the County of ______________, during my continuance in office, according to law, to the best of my knowledge and ability, without favor or affection to any party, and that I will only receive my legal fees. So help me God."