τὴν σφραγῖδα κυρίου. The word σφραγίς was very widely used in the primitive Church to denote baptism. See Suicer’s Thesaurus for examples. Gregory Nazianzen, in his Orat. XL., gives the reason for this use of the word: “We call baptism a seal,” he says, “because it is a preservative and a sign of ownership.” Chrysostom, in his third Homily on 2 Cor. §7, says, “So also art thou thyself made king and priest and prophet in the laver; a king, having dashed to earth all the deeds of wickedness and slain thy sins; a priest, in that thou offerest thyself to God, having sacrificed thy body and being thyself slain also; …a prophet, knowing what shall be, and being inspired by God, and sealed. For as upon soldiers a seal, so is also the Spirit put upon the faithful. And if thou desert, thou art manifest to all. For the Jews had circumcision for a seal, but we the earnest of the Spirit.” (Nicene and Post-Nicene Fathers, First Series, Vol. XII. p. 293.)