Today is Trinity Sunday in the church liturgical calendar. Growing up in a non-liturgical church I had never even heard of Trinity Sunday until I was an adult. In fact, I hardly ever heard of the doctrine of the Trinity during most of my childhood. I can still remember the first sermon I heard that was devoted to the doctrine. I was a young adult in my early twenties. I have since then preached on the Trinity quite often. I have even taught several adult classes on the doctrine. But I do not recall, at least from my background, a single sermon specifically on the Trinity. This is one of the real weaknesses of not following some kind of liturgical form that requires the whole church to deal with the central mysteries of our great common faith week-to-week.
In the New Testament what is to be "confessed," as well as "believed," is Jesus Christ (cf. Romans 10:9-10 and Philippians 2:10-11). But very early the Christian Church understood that "confessing" and "believing" in Jesus involved more than human emotions and an a-historical faith experience. Believing and confessing have always been seen as correlatives in the New Testament and in the life of the early church. Added to these two is a third, teaching. We believe in Jesus as the revelation of God, thus we confess and teach.
The earliest Christian Creeds all addressed one central question: "Who is God?" The answer always took believers back to Jesus, and then from Jesus the church was required to address the issue of the Father and the Holy Spirit, thus the Trinity. Various analogies were developed to help explain the doctrine, particularly by great thinkers such as St. Augustine. In the end the church formulated a doctrine that no one can fully grasp, since the Athanasian Creed rightly refers to God as "incomprehensible." We can, and we must, rightly explain and defend our faith but we cannot comprehend the magnitude or mystery of it, ever.
In a very real sense "the doctrine by which the church stands or falls" must be the Trinity. If we do not confess the Trinity we do not confess Christ and thus we deny the kerygma. Without this Gospel of God we are lost and without hope. The Nicene Creed, which we recited today on Trinity Sunday, has three stanzas. Each stanza begins with similar words: "We believe in one God, the Father, the Almighty . . . We believe in one Lord, Jesus Christ, the only Son of God . . . [and] We believe in the Holy Spirit, the Lord, the giver of life . . . "
A robust doctrine of the Trinity would bring much life to the church in our time. I believe that we will not recover a proper understanding of God’s love for us until we reconnect this love to the Trinity.