Article VI, section II, paragraph 1 of the New Jersey Constitution provides that "…Five members of the court shall constitute a quorum. When necessary, the Chief Justice shall assign the Judge or Judges of the Superior Court, senior in service, as provided by rules of the Supreme Court, to serve temporarily in the Supreme Court." The implementing rule, R.2:13-2(a), provides "Five members of the court shall constitute a quorum. When necessary to constitute a quorum, to replace a justice who is absent or unable to act, or to expedite the business of the court, the presiding justice may assign one or more retired justices of the Supreme Court who are not engaged in the practice of law and who consent thereto or the judge or judges of the Appellate Division, senior in length of service therein, to serve temporarily in the Supreme Court."