1 John 5:6

οὗτος, i.e., this Jesus who is the Son of God, the Messiah whom the prophets foretold and who “came” in the fulness of the time. ὁ ἐλθών, not ὁ ἐρχόμενος. His Advent no longer an unfulfilled hope but an historic event. διά, of the pathway or vehicle of His Advent. Ἰησοῦς Χριστός, “Jesus Christ,” one person in opposition to the Cerinthian “dissolution” (λύσις) of Jesus and Christ (see note on 1 John 4:3). ἐν. He not only “came through” but continued “in the water and in the blood,” i.e., His ministry comprehended both the Baptism of the Spirit and the Sacrifice for sin. Perhaps, however, the prepositions are interchangeable; cf. 2 Corinthians 6:4-8; Hebrews 9:12; Hebrews 9:25. ἡ ἀλήθ.: Jesus called Himself “the Truth” (John 14:6), and the Spirit came in His room, His alter ego (1 John 5:16-18).