“The link between the gospel and the Trinity is Christ’s incarnate mediatorial work.
The Father’s work revolves around the mission of the Son whom He sent into the world.
The Son’s work is never abstracted from His taking human nature, walking by faith, living in human obedience to God’s law, suffering and dying under the penalty of that law, and rising again to receive God’s blessing– all on behalf of His people.
The Spirit empowered the incarnate Son and comes to His people through His mediation. Thus, the Trinitarian gospel is Christ-centered.
The gospel is essentially Trinitarian. Every member of the Trinity performs an indispensable function in our salvation.
Without God the Father, there would be no one to send the Son and Spirit into the world, to accept the Son’s sacrifice, or to hear the Spirit-wrought prayers of the redeemed.
Without the obedience and sufferings of God the Son, no one could escape God’s curse or enjoy God’s blessing in the Spirit.
Without the renewing work and indwelling presence of God the Spirit, no one would benefit from Christ’s redemptive work or have any assurance of being reconciled to God as his child. Apart from the divine Spirit, God could not dwell within the hearts of the redeemed to relate them to the Father and the Son.
Without the Trinity, the gospel disappears.
Ryan McGraw says, ‘The greatest proof of the doctrine of the Trinity is that the authors of the New Testament could hardly explain the Gospel without it.’
How fervently we should love the doctrine of the Trinity! Too often it is consigned to the dusty shelves of confessed but neglected doctrines– regarded as abstract dogma without practical implications.
In reality, however, the triune God is the only Savior. We should cherish this doctrine, study it in the Holy Scriptures, meditate upon it until it inflames our hearts, and teach and defend it with all the resources of the church.”
–Joel R. Beeke and Paul M. Smalley, Reformed Systematic Theology, Volume 1: Revelation and God (Wheaton, IL: Crossway, 2019), 1: 879.