The Holy Trinity by Dumitru Staniloae

Because it is without beginning, supreme existence is eternally happy in and of itself without needing to develop at all. In order to reach this state and unite themselves with supreme existence, created beings need to make an effort of their own free will. They can only progress through that freedom that has been given to them as they follow laws that are an expression of the good will of God, or of supreme Reason. But once reason has been given to them, they can use it to oppose the good that supreme Reason and its laws demand of conscious things. They can use reason in a distorted manner to justify orienting themselves toward deceitful goals, or to promote their own egoism. Goodness desires to rest in a free harmony established among conscious things and between them and God. But selfishness opposes the good, and therefore opposes God. It ruptures the Reason that brings harmony among all things, and between everything and God. This shows once again the creation too must contribute something if it is to have unity with God. But the Holy Trinity, in which the most perfect harmony and love reside, helps creation makes its contribution. The Son of God Himself helps humanity realize this unity. The Father uses the Son, just as He uses Reason, for the sake of creation.

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