Mass. R. Evid. 610
Evidence of a witness's religious beliefs or opinions is not admissible to attack or support the witness's credibility.
Mass. Guid. Evid. 610
This section is derived from Commonwealth v. Dahl, 430 Mass. 813, 822-823 (2000), and G. L. c. 233, § 19 ("evidence of [a person's] disbelief in the existence of God may not be received to affect his credibility as a witness"). See also Commonwealth v. Gonsalves, 488 Mass. 827, 842-843 (2022) (error to admit witness's statement that she "spoke to God" before deciding to testify against defendant). Though not admissible as to credibility, evidence that relates to a person's religious beliefs is not per se inadmissible. See Commonwealth v. Kartell, 58 Mass. App. Ct. 428, 436-437 (2003) (evidence of defendant's religious beliefs admissible for relevant purpose of showing defendant was jealous of victim); Commonwealth v. Murphy, 48 Mass. App. Ct. 143, 145 (1999) (to establish that a child witness is competent to testify, "a question whether the child believes in God and a question whether the child recognizes the witness's oath as a promise to God are within tolerable limits to test whether the witness's oath meant anything to the child witness").