E. Cobham Brewer 18101897. Dictionary of Phrase and Fable. 1898.
Peace of God.
In 1035 the clergy interfered to prevent the constant feuds between baron and baron; they commanded all men to lay down their arms on pain of excommunication. The command and malediction were read daily from the pulpits by the officiating priests after the proper gospel:May they who refuse to obey be accursed, and have their portion with Cain, the first murderer; with Judas, the arch-traitor; and with Dathan and Abiram, who went down alive into the pit. May they be accursed in the life that now is; and in that which is to come may their light be put out as a candle. So saying, all the candles were instantly extinguished, and the congregation had to make its way in the dark out of church as it best could.