VATICAN CITY (CNS) — While intellectually difficult to understand, the mystery of the Holy Trinity is understood in one’s heart as the revelation of God’s love for all men and women, Pope Francis said.

The Christian belief that the persons of the Holy Trinity “are not three gods” but rather “one God in three persons” speaks to the heart because “we find it encompassed in that expression of St. John which summarizes all of revelation: ‘God is love,'” the pope said May 30 before reciting the Angelus prayer with pilgrims gathered in St. Peter’s Square.

Love, he said, “is essentially a gift of self and in its original and infinite reality it is the Father who gives himself by generating his Son, who in turn gives himself to the Father, and their mutual love is the Holy Spirit, the bond of their unity.”

In his address, the pope reflected on the day’s feast of the Most Holy Trinity, which celebrates God as Father, Son and Holy Spirit.

“Today we stop to celebrate this mystery because the persons are not adjectives of God, no. They are real, diverse, different persons; they are not — as that philosopher used to say — ’emanations of God,’ no, no! They are persons,” he said.

Acknowledging that the mystery of the Holy Trinity “is not easy to understand,” the pope said Christians “can live this mystery, all of us, we can live a great deal.”

In revealing the triune nature of God, he explained, Jesus showed all “the face of God as a merciful father,” himself as the Son of God “who gives his life for us” and the Holy Spirit as the “spirit of truth” that proceeds from the father and the son.

“Today’s celebration, therefore, makes us contemplate this marvelous mystery of love and of light from which we come and toward which our earthly journey is guided,” he said.

Recalling the Sunday Gospel reading in which Christ tells the disciples to baptize in the name of the Father, the Son, and the Holy Spirit, Pope Francis said Christians “cannot overlook the unity to which Jesus calls us.”

“The beauty of the Gospel needs to be lived — unity — and witnessed to in the harmony among us, who are so diverse! And this unity, I dare say, is essential to Christians: it is not an attitude, a manner of speaking, no; it is essential, because it is the unity that is born from the love and the mercy of God, from the justification of Jesus Christ and from the presence of the Holy Spirit in our hearts.”