Capes Trinity and Eternity, Saguenay River, Quebec, Canada
The doctrine of the Trinity is the most immense of all the doctrines of religion. It is the foundation of theology. Christianity, in the last analysis is Trinitarianism. Take out of the New Testament the persons of the Father, the Son, and the Holy Spirit, and there is no God left. Take out of the Christian consciousness the thoughts and affections that relate to the Father , the Son, and the Holy Spirit, and there is no Christian consciousness left. The Trinity is the constitutive idea of evangelical theology, and the formative idea of the evangelical experience. The immensity of the doctrine makes it of necessity a mystery; but a mystery which like night enfolds in its unfathomed depths the bright stars–points of light, compared with which there is no light so keen and glittering. Mysterious as it is, the Trinity of the Divine Revelation is the doctrine that holds in it all the hope of man; for it holds within it the infinite pity of the Incarnation and the infinite mercy of the Redemption.
And it shares its mysteriousness with the doctrine of the Divine Eternity. It is difficult to say which is most baffling to the human comprehension, the all-comprehending, simultaneous, successionless consciousness of the Infinite One, or his trinal personality. Yet no theist rejects the doctrine of the Divine eternity because of its mystery. The two doctrines are antithetic and correlative. On one of the Northern rivers stand two cliffs fronting each other, shooting their pinnacles into the blue ether, and sending their roots down to the foundations of the earth. They have name them Trinity and Eternity. So stand, antithetic and confronting, in the Christian scheme, the trinity of the eternity of God.
— William G. T. Shedd in his "Introductory Essay" to A. H. Haddan’s translation of On the Trinity by Augustine of Hippo as found in NPNF vol. 3, pp. 10-11.