The fundamental theorem of Christianity is that God is love. In Judaism and Islam one would say: “God loves. God loves the world and everyone. ” These seems to be synonymous with the concept proclaimed by Christianity, but the difference in our talk about God is that love is not just what God does, but that God IS love.
This declaration forms the basis of the teaching about the Holy Trinity. Chesterton said that we have a problem with the doctrine of the Holy Trinity, because it appears to us as a medieval concept, and not particularly clear. Nevertheless, at the same time everyone enthusiastically accepts the truth that God is love. These two statements are really one and the same. Since we are talking about the fact that God is love, we mean that he is: one who loves (God the Father), one that is loved (the Son of God) and the Love they show each other (the Holy Spirit).
Inspiring in this context is also the fact that in this relationship there is a place for us as well. Participating in the life of the Trinity is to take on the challenge of love. Openness to the fact that God is loving and loved. The trust in the love that surrounds all persons of the Trinity and me. In the love that in God is perfect, open, infinite and devoid of all, that human love sometimes can be. In this sense, the dogma of the Holy Trinity seems to us closer and more understandable.
R. Barron, What is the Trinity?, Los Angeles 2009.