ISB ~ 1 John 5 v8

three witnesses:Evidence of Christ’s humanity is present in the liturgy, where the Spirit never ceases to bring Christ to the world through the water of Baptism and the blood of the Eucharist. Faith in the Incarnation is thus supported by the joint testimony of history and liturgy.

John was uniquely qualified to insist on this:he not only engaged in sacramental ministry, but he was the sole apostle to witness the Spirit, the water, and the blood come forth from the crucified body of Jesus (Jn 19:30, 34) (CCC 1108, 1225). See note on Jn 19:34.

• The Mosaic Law requires joint testimony from two or three witnesses to uphold a claim in court (Deut 19:15). For other uses of this legal standard in the NT, see Jn 5:30-47 and 2 Cor 13:1.

• The three witnesses become one in Baptism, for if you eliminate one of them, the sacrament ceases to be. Without the Cross of Christ, water is simply a natural element. Without water, there is no mystery of regeneration. And unless one is baptized in the name of the Father, the Son, and the Holy Spirit, there is neither remission of sins nor reception of spiritual grace (St. Ambrose, On the Mysteries 4, 20).