Such commissioners shall be immediately notified of their appointment by the clerk, and before entering upon the discharge of their duties shall take and subscribe an oath or affirmation before the clerk of such court in the following form: “I do solemnly swear (or affirm) that I will honestly, without favor or prejudice, perform the duties of jury commissioner during the year; that in selecting persons to be drawn as jurors, I will not select any person I believe to be disqualified or exempt from serving as a juror; that I will select none whom I have been requested to select; and that in all my selections I will endeavor to promote only the impartial administration of justice.”