Interruption of Mass

Is it Lawful to Discontinue a Mass?—(a) To terminate Mass before the end has been reached is unlawful unless there be a serious reason; otherwise, disrespect is shown the Holy Sacrifice. A grave reason (e.g., sudden sickness) suffices if Mass be discontinued before the Consecration; a most grave reason (i.e., danger of death or of profanation of the Sacrament) if Mass be discontinued between the Consecration and the Communion. But a Mass that is broken off after the Consecration and before the Communion must be completed by the celebrant or another, at least if this can be done within an hour from the time of cessation; else the sacrifice is mutilated.

(b) To interrupt Mass is also unlawful without serious cause. Thus, a grave reason excuses an interruption outside the Canon, for example, to preach a sermon after the Gospel or Communion; but only a very grave reason excuses an interruption during the Canon, for example, a sick call to give a necessary Sacrament (Baptism, Penance, Extreme Unction, or Viaticum) to a dying person.