Common Statements of the Emanation of the Divine Essence
The common statements in the patristic trinitarianism respecting this emanation of the essence are the following: The Son is from the Father, not as an effect from a cause; not as an inferior from a superior; not as created finite substance from uncreated infinite substance; but as intelligence is from intellect, the river from the spring, the ray from the sun.
William G. T. Shedd, Dogmatic Theology, ed. Alan W. Gomes, 3rd ed. (Phillipsburg, NJ: P & R Pub., 2003), 246.