God the Father, You are this good; this good is Your Word, that is, Your Son.
For in the Word which You Yourself utter, there can be nothing other than Yourself, or anything greater or less than You.
For Your Word is true just as You are true, and so it is the Truth that is You Yourself and no other.
You are one, and from You nothing can be born except Yourself.
And this is the One love, between You and Your Son - the Holy Spirit which proceeds from You both.
This Love is nothing less than You and Your Son; for Your love for Him and He for You are as great as You are.
That which is no different from You and Him is not something other than You and Him, for there cannot proceed from the height of Your oneness anything that is not Yourself.
So Father, Son, and Holy Spirit is wholly as Trinity what each is in Himself; for each is none other than the highest single unity and the highest unity of persons, which can neither be multiplied nor made other.
-- St. Anselm of Canterbury, Proslogion, Chapter 23