Today, the liturgy celebrates the Solemnity of the Most Holy Trinity almost to underline that in the light of the Pascal Mystery is fully revealed the center of the universe and of history: God himself, eternal and infinite Love. The word that summarizes all revelation is this: "God is love" (1 John 4:8,16); and love is always a mystery, a reality that surpasses reason without contradicting it, and more than that, exalts its possibilities. Jesus revealed to us the mystery of God: he, the Son, made us know the Father who is in Heaven, and gave us the Holy Spirit, the Love of the Father and of the Son. Christian theology synthesizes the truth of God with this expression: only one substance in three persons. God is not solitude, but perfect communion. For this reason the human person, the image of God, realizes himself or herself in love, which is a sincere gift of self.
Pope Benedict XVI, ANGELUS, May 22, 2005