We are gathered to worship the triune God. The fact that He is triune is not a side doctrine; it is at the very center of who we are. It is not the case that we believe that monotheism is “basic,” and that our particular form of monotheism affirms this extra truth. All unitarian conceptions of god are idols. The unity of God is no more basic than His Godhead in three persons. The tri-personality of God gives rise to His unity, and His unity gives rise to His triune communion. The Trinity is not to be thought of in static terms at all. Everlasting begetting, constant speaking, the Word always spoken, the light always shining. Think of a waterfall, with no top, no bottom, and no sides—and then realize that this does it no justice.
We are taught in many places in Scriptures that we become like what we worship. Those who make idols become as blind and stupid as blocks of wood or stone, as we are taught in Psalm 115. We will come to be conformed fully to the image of Christ (to which we are predestined) when we finally see Him as He is. In the meantime, as we behold His face by faith in our worship of Him, we are being transformed from one degree of glory to another. We become like the God we worship, just as idolaters become like the gods they worship.
So if we are formally Trinitarian (in our statement of faith somewhere), but it does not translate to a self-conscious adoration of God the Father, in the name of Jesus Christ, in the power of the Holy Spirit, then we will drift far away from our statement of faith in our practical experience.
Our triune God is love, because from all eternity, for each of them, there have always been two Beloveds. The Godhead is a family; the Godhead is a community. God is love. But the solitary, unitarian God is the ultimate loner, the ultimate hermit, the ultimate unmarried bachelor. And the dour and prim countenance of many who claim to be Trinitarians betrays that something else is going on—some other kind of worship is occurring. Because, over the long term, the transforming process of worshipping your God or gods is inexorable. It cannot be stopped or diverted. Your face will eventually be completely conformed to the face that you bow down to.
We are Christians, so let us worship the Father through Jesus Christ, in the power of the Spirit.