The following oath shall be administered to jurors in criminal cases: "You swear, that in all causes committed to you, you will give a true verdict therein, according to the law and evidence given you. So help you God." Any juror, conscientiously scrupulous of taking an oath, may affirm in the mode described in section 1253.   [PL 1979, c. 541, Pt. B, §21 (AMD).]