First, from Octavius Winslow's Morning Thoughts:
The doctrine of the Trinity is to the Christian the key of the Bible. The Spirit imparting skill to use it, and the power, when used, it unlocks this divine arcade of mysteries, and throws open every door in the blest sanctuary of truth. But it is in the light of salvation that its fitness and beauty most distinctly appear—salvation in which Jehovah appears so inimitably glorious—so like Himself. The Father's love appears in "sending" His Son; the Son's love in "undertaking" the work; the Holy Spirit's love in "applying" the work. Oh, it is delightful to see how, in working out the mighty problem of man's redemption, the Divine Three were thus deeply engaged. With which of these could we have dispensed? All were needed; and had one been lacking, our salvation would have been incomplete, and we would have been eternally lost. In bringing to glory the church they thus have saved, the sacred Three are solemnly pledged.
And this from Jared Wilson's Gospel Deeps: Reveling in the Excellencies of Jesus:
Do you see how the Trinity hems us in? We have no defense against this brilliant triangle offense. Praise Jesus! "The salvation that was planned by the Father has been procured by the Son and is now presented and protected by the Spirit" (Ryken and LeFebvre, Our Triune God).
The glory of God is exponentially and eternally magnified by God's triune self. "Holy, holy, holy, is the Lord God Almighty, who was and is and is to come!" (Rev. 4:8). His holiness is threefold-perfection deep and wide and high and long. "Holy, holy, holy is the Lord of hosts; the whole earth is full of his glory!" (Isa. 6:3). One day the knowledge of God's glory will cover the earth like the waters cover the sea (Hab. 2:14). He will have the universe covered from every angle—it's divine geometry—as he has us covered now.
"May grace and peace be multiplied to you."
The Trinitarian gospel is immediately practical because it entails that Christ is our advocate (1 John 2:1) and intercessor (Heb. 7:25) at this very moment and that the Spirit also is buttressing our prayers (Rom. 8:26).
With salvation's rapture into the life of the Trinity, God isn't just commanding us to grace and peace, he is praying for it himself to himself, he is bestowing it himself through himself, he is declaring it himself through himself authoritatively. The result of salvation is that "those who are elect exiles according to God's foreknowledge, the Spirit's sanctification, and the Son's atoning work" receive grace and peace in multiplying (by threes?) abundance. This is incredibly good news.
We are saved from God to God by God through God for God. The godhead works in concert so that salvation will engulf you in God. (pp. 74-75)