‘The supreme revelation is that God is love: note the full meaning and significance of the words, not God does, can, will love, but the simple statement He is Love. We can only partially understand because the revealed truth and the fullest revelation is given in the Person, life and teaching of Jesus Christ, the Second Person of the Holy Trinity. From Him St John, the great apostle of the love of God, learnt the truth. In his Gospel and epistles he regards this as the primary fact in the revealing of truth. God is love, and in the Godhead Himself, which we try to explain by the doctrine of the Holy and Undivided Trinity. Our Lord speaks of God not as a solitary being but as One. Within the oneness of the Godhead He thinks, acts, loves in a Trinity of personal relationships, Father, Son, and Holy Spirit. It is this which Christians come to understand from the revelation of Jesus Christ. In the Holy Scripture there is not an exact definition, yet you find apostolic writers and ancient Fathers without any sense of contradiction speaking of one God, and of God the Father, Son and Holy Spirit. The Holy Spirit led them all into truth and the best language that could be found for leading us to understand something of the Godhead is the Holy and Undivided Trinity’.

​Raymond Raynes CR, 1903-1958

O eternal God! O eternal Trinity! Through the union of thy divine nature thou hast made so precious the blood of thine only-begotten Son! O eternal Trinity, thou art as deep a mystery as the sea, in whom the more I seek, the more I find; and the more I find, the more I seek. For even immersed in the depths of thee, my soul is never satisfied, always famished and hungering for thee, eternal Trinity, wishing and desiring to see thee, the true Light.
 
O eternal Trinity, with the light of understanding I have tasted and seen the depths of thy mystery and the beauty of thy creation. In seeing myself in thee, I have seen that I will become like thee. O eternal Father, from thy power and thy wisdom clearly thou hast given to me a share of that wisdom which belongs to thine Only-begotten Son. And truly hast the Holy Spirit, who proceedeth from thee, Father and Son, given to me the desire to love thee.
 
O eternal Trinity, thou art my maker and I am thy creation. Illuminated by thee, I have learned that thou hast made me a new creation through the blood of thine Only-begotten Son because thou art captivated by love at the beauty of thy creation.
 
O eternal Trinity, O Divinity, O unfathomable abyss, O deepest sea, what greater gift could thou givest me then thy very Self? Thou art a fire that burns eternally yet never consumed, a fire that consumes with thy heat my self-love. Again and again thou art the fire who taketh away all cold heartedness and illuminateth the mind by thy light, the light with which thou hast made me to know thy truth.
 
By this mirrored light I know thou are the highest good, a good above all good, a fortunate good, an incomprehensible good, an unmeasurable good, a beauty above all beauty, a wisdom above all wisdom, for thou art wisdom itself, the food of angels, the fire of love that thou givest to man.
 
Thou art the garment covering our nakedness. Thou feedest our family with thy sweetness, a sweetness thou art from which there is no trace of bitterness. O eternal Trinity! Amen.

A prayer to the Most Holy Trinity by St Catherine of Siena, 1347-1380

‘O eternal Trinity, eternal godhead! This godhead, your divine nature, made immensely precious the blood of the only-begotten Son. Eternal Trinity, you are like a deep sea, in which the more I see, the more I find; and the more I find, the more I seek you. You fill the soul, yet somehow without satisfying it: In the abyss which you are you so fill the soul that it ever continues to hunger and thirst for you, desiring you, eager in your light to see you, who are the light.

With the light of my understanding, in your light I have tasted and seen the abyss which you are, eternal Trinity, and the beauty of your creation. Then looking at myself in you, I have seen that I am your image; this is a gift that I receive from you in your power, eternal Father, and in your wisdom, which is attributed to your only-begotten Son. The Holy Spirit who proceeds from you, Father, and from your Son has prepared me, giving me a will to love you.

Eternal Trinity, you are the Creator, I the creature. I have come to know, in the new creation you made of me in the blood of your Son, that you are in love with the beauty of your creature’.

from her Dialogue by St Catherine of Siena, 1347-1380

O merciful God, who gavest to thy servant Saint Catherine of Siena a wondrous love of the Passion of Christ: grant that, through her prayers; we thy people may be united to him in his majesty and rejoice for ever in the revelation of his glory; who liveth and reigneth with thee, in the unity of the Holy Ghost, ever one God, world without end. Amen. - Divine Worship: The Missal​