105. Notice, also, that the appearance of the mystery three times repeated expressed the operation of the Trinity. And so in the mysteries The “mysteries” are the sacrament of baptism, and the “three-fold question” those which preceded baptism, viz.: Dost thou believe in God the Father Almighty? Dost thou believe in our Lord Jesus Christ, and in His cross? and Dost thou believe in the Holy Spirit? with the answer, “I believe,” to each, as mentioned by the author of De Sacramentis, II. 7 (written probably in the 5th or 6th century). the threefold question is put, and the threefold answer made, and no one can be cleansed but by a threefold confession. For which reason, also, Peter in the Gospel is asked three times whether he loves the Lord, that by the threefold answer the bonds of the guilt he had contracted by denying the Lord might be loosed.