The question of the proper starting point, the “first principles” of theology is one to which those engaged in its discipline must continually return; however, their continual temptation is to do otherwise. Without being firmly grounded on its proper foundation, the vast body of reflection developed in theology risks collapsing into dust. It is not simply that the first principles are elementary stages, to be transcended by higher realms of more elevated reflection, but that they provide the necessary perspective within which the more abstract discussion takes place and is to be understood. The proper order, the taxis, of theology must be maintained if it is to retain its proper coherence. … Christian theology developed first and foremost as faith in the lordship and divinity of the crucified and exalted Christ, as proclaimed by the apostles according to the Scriptures. The Passion of Christ stands as the definitive moment in the revelation of God, the eschatological apocalypse which unlocks the Scriptures, and so enables Christians, retrospectively, to view the work of God from the beginning and, prospectively, by the continued contemplation of the exalted Christ who is still the coming one, to participate in this work, embodying or incarnating the presence of God in this world through their own witness or martyria. …

The way to Nicaea is not plotted retrospectively from Nicaea, as if it were itself the starting point, but with reference to the revelation of God in Christ, the subject of the Christian confession from the beginning; if Nicaea is a definitive moment in Christian identity, it is because it preserves the truth of the definitive moment. If we overlook this basic fact, then we risk both misunderstanding the landmarks that we think we already know and, more seriously, substituting other principles, taking something other than Christ and his Cross as constitutive of the identity of Christianity.

John Behr. The Nicene Faith. Part One, True God of True God. Crestwood, N.Y.:  St Vladimir’s Seminary Press, 2004. 1-2.