God is not fully known when He is only “known” by the understanding.
He is best known by us when He takes possession of our whole being and unites us to Himself.
Thomas Merton, Bread in the Wilderness
It is the “great mystery of Godliness” which occupies him (Saint Bernard) before all else.
What is that mystery?
Not an idea, not a doctrine, but a Person: God Himself, revealed in the Man, Christ.
How is this doctrine understood?
When the Person is known.
How is He known?
When He lives in us and is Himself our love for His Father.
Loving the Father in us, He makes us one with the Father as He Himself is.
Thomas Merton, Last of the Fathers