Expositor's Bible Commentary Commentary 1 John 4:2

"Hereby know ye the Spirit of God: every spirit that confesseth that Jesus Christ is come in the flesh is of God:" — 1 John 4:2 (ASV)

The test itself appears to hinge on the words “that Jesus Christ has come in the flesh.” The false prophets may well have believed that Christ was the Savior of the world, but they denied the connection between the divine Christ and Jesus of Nazareth. At least they clearly denied that “the Christ” ever had come “in the flesh.” The clause “that Jesus Christ has come” reflects the author’s clear view of the preexistence of the Son, who came from the Father and from the moment of his historical birth was Jesus Christ in the flesh.

How does this confession give evidence of the Spirit? For John, as for Paul, the truth of the Christian Gospel is hidden from the world (cf. 1 Corinthians 2:7–16). Only because there is a divine intervention and the darkness is removed can the light of the Gospel be recognized (cf. 4:6).