"And there are three that bear witness in earth, the Spirit, the Water (the Word), and the blood: and these three agree in one."
Notice how the order is given. The witnesses to Christ's Deity are, first, the Word, then the blood, and then the Spirit. The witnesses to redemption's accomplishment are, first, the Father, then the Son, and then the Spirit. The witnesses to our saving interest in Christ are, first, the Spirit, then the Word, and then the blood.
1. A SAVING KNOWLEDGE OF CHRIST BEGINS WITH THE REVELATION OF THE SPIRIT (I Cor. 2:9-10). No one on earth can know and be firmly persuaded that he is one of God's elect, one of those for whom Christ died, but by the special revelation of God the Holy Spirit. No man can, or should, convince another of his salvation in Christ. Only the Spirit of God can convince a sinner of grace and salvation in Christ (John 16:8-14). And if he convinces, you are convinced. He is called the Comforter because he conveys to our hearts the comfort of our election, redemption, salvation, and eternal acceptance with God (Rom. 8:14-17). At the time appointed, he manifests the glory of Christ's Person and the merits of his work, creating faith in the hearts of elect sinners (2 Cor. 4:6; Gal. 1:15; 2 Tim. 1:9-10; Tit. 1:2-3; 2 Pet. 1:18-20).
2. THIS SAVING KNOWLEDGE OF CHRIST IS BASED UPON THE RECORD OF THE WRITTEN WORD OF GOD, SYMBOLIZED BY WATER (Tit. 3:5). The Spirit never operates independently of his written Word. He reveals Christ supernaturally in the hearts of men. But he reveals Christ only through the instrumentality of gospel preaching. He takes the record of God in his Word and makes it the voice of God in a man's heart! He declares in our hearts that our redemption is accomplished by Christ's obedience and death as our Substitute (Heb. 9:12-14)
3. THIS SAVING KNOWLEDGE OF CHRIST IS NEITHER MORE NOR LESS THAN FAITH IN HIS BLOOD. Faith is the echo of my heart to the voice of God's Spirit speaking to me by the gospel. The warrant of my faith is the Word of God alone. And the warrant of my assurance is faith alone (1 John 5:9-13). Faith fetches full assurance to the believer's heart, not from within, but from without, from the precious blood of the Lord Jesus Christ and the naked Word of God.