“For we ourselves were once foolish, disobedient, led astray, slaves to various passions and pleasures, passing our days in malice and envy, hated by others and hating one another. But when the goodness and loving kindness of God our Savior appeared, he saved us, not because of works done by us in righteousness, but according to his own mercy, by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly through Jesus Christ our Savior, so that being justified by his grace we might become heirs according to the hope of eternal life.”
—Titus 3:3–7

He [the Father] saved us… by the washing of regeneration and renewal of the Holy Spirit, whom he poured out on us richly through Jesus Christ our Savior.” The Holy Spirit is poured out on us richly by the Father through Jesus Christ. The Spirit was purchased for us by Christ our Savior. He was so purchased that He is poured out on us “richly.” If the Spirit is special sauce of our salvation, the Father has so slathered Him on through the Son that the entree could be mistaken for a soup. How does the Father look on the work of the Son? Because of the Son, He not only pours out the Spirit, He pours Him out richly on us. He pours infinity on you, richly.
Our salvation is from the Father, through the Son, and by the Spirit. Our salvation originated in the Father, was secured by the Son, and is effected by the Spirit. The Father determined, gave and sent; the Son lived, died, and rose; and the Spirit regenerates, seals, and sanctifies.
Speaking in a strictly metaphorical way, Irenaus said that the Father has two hands, the Son and the Spirit. Our God is ambidextrous and He always uses both of His hands. God is a Tri-unity of persons. Their operations are inseparable. Where God works, all three persons work. Where you find one working, the others are working (John 5:17, 19). God creates and recreates using both hands. The Father saves you by two sendings: the sending of the Son and the sending of the Spirit. The gracious sending of the Son purchases the sending of the Spirit. The Son was sent to accomplish salvation and the Spirit was sent to apply that salvation.
These sendings are self-sendings of our Triune God. Fred Sanders explains, “when God the Father sends the Son and the Spirit, we meet God in sendings that have an infinite depth behind them: self-sendings in which God sends God; sendings in which God is God with us.” God, though God, has given you God as the guarantee of giving you God in full and forever. The Father, through the Son, has given you the Spirit, as the guarantee of Him giving you Himself in full and forever. This is the Trinitarian shape of your salvation. The Trinity is not a distant doctrine; it is the very substance of your salvation.