1 John 5:7

The Holy Spirit testified to the identity of Jesus as God’s Son at His baptism (Matthew 3:17). Cerinthus taught that the Spirit was the divine Christ, God’s anointing, which descended on Jesus then. [Note: See Hodges, The Epistles . . ., p. 219, footnote 10.] John corrected this error by pointing out that the Spirit was a witness to Jesus’ identity, not the Christ. John further stressed the reliability of the Spirit’s witness by reminding his readers that the Spirit is truth. The Spirit’s testimony about Jesus’ identity at His baptism was true because the Spirit Himself is truth, even God Himself (cf. John 14:6).