The testimony of the Holy Spirit is not a private opinion but the witness of the church of all ages, of Christianity as a whole, of reborn humankind in its entirety. At one time the church in all of its members, like the world, was hostile to the word of God. But the Holy Spirit, working in it and with it, took up the defense of the truth of Christ. He has broken its enmity, illumined its intellect, bent its will, and keeps it in touch with the truth from century to century and from day to day. The whole testimony of the believing community is a testimony to the Holy Spirit. It is the “yes!” and “Amen!” which that community utters in response to the truth of God. It is the “Abba! Father! Your word of truth” that rises up from the hearts of all believers. The testimony of the Holy Spirit is so far from being the Achilles’ heel of Protestantism that it should rather be called the cornerstone of our Christian confession, the crown and seal of all Christian truth, the triumph of the Holy Spirit in the world. Take away the testimony of the Holy Spirit, not only in relation to Scripture, but to all the truths of redemption, and there is no more church. For the witness the Holy Spirit bears to Scripture as the word of God is but a single tone in the song he has put on the lips of the believing community. It is but a small part of that splendid divine work assigned to the Holy Spirit: to cause the fullness of Christ to dwell in his community.
Reformed Dogmatics Vol. 1: Prolegomena (Grand Rapids, Michigan; Baker Academic; 2003) p. 599.