What is Declared Concerning Christ Rendered to Us by the Secret Operation of the Spirit
by John Calvin (abridged)1,2
1. What Christ has received from His Father is nothing to us, till we are united to Him. Though it is true that we obtain this by faith, we see that the communication of Christ, offered in the Gospel, is not embraced by all. This leads us to inquire into the secret energy of the Holy Spirit, by which we are introduced to the enjoyment of Christ and all His benefits.
In 1 John 5:6,
This is He that came by water and blood, even Jesus Christ; not by water only, but by water and blood. And it is the Spirit that bears witness, because the Spirit is truth. (KJVER)
it is declared that Christ came by water and blood that the Spirit may testify concerning Him. It is the Spirit that seals the ablution [cleansing] and sacrifice of Christ. For which reason Peter also says, that believers are “elect . . . through sanctification of the Spirit, unto obedience and sprinkling of the blood of Jesus Christ” (1 Peter 1:2). This passage suggests to us, that our souls are purified by the secret ablution of the Spirit, that the effusion of that sacred blood may not be in vain. For the same reason also Paul, when speaking of purification and justification, says, we enjoy both “in the name of the Lord Jesus, and by the Spirit of our God” (1 Corinthians 6:11). The sum of all is this—that the Holy Spirit is the bond by which Christ efficaciously unites us to Himself.