In the Beginning, not in time or space,
But in the quick before both space and time,
In Life, in Love, in co-inherent Grace,
In three in one and one in three, in rhyme,
In music, in the whole creation story,
In His own image, His imagination,
The Triune Poet makes us for His glory,
And makes us each the other’s inspiration.
He calls us out of darkness, chaos, chance,
To improvise a music of our own,
To sing the chord that calls us to the dance,
Three notes resounding from a single tone,
To sing the End in whom we all begin;
Our God beyond, beside us and within.
So reads Fr Malcom Guite’s Sonnet on the Holy Trinity. 

The mystery of the Holy Trinity is just that… A Mystery. I think it is best described in Poetry, In Song and in Art. One famous example being the 15 th Century Painting of the Holy Trinity that was discovered and restored in this last century between 1905-1918.  
Holy Trinity Icon

“Andrei Rublev was born circa 1360. Little is known of his early life however, his name is associated with the history of the Moscow artistic school. Many of his works, just as those of his disciples and followers, originated in Moscow or in towns and monasteries around it. His works can be viewed in both the Tretyakov Gallery in Moscow and the Russian Museum in St. Petersburg . He died on January 29, 1430 and is buried at the Andronikov Monastery in Moscow .
This icon takes as its subject the mysterious story where Abraham receives three visitors as he camps by the oak of Mamre. He serves them a meal. As the conversation progresses he seems to be talking straight to God, as if these ‘angels’ were in some way a metaphor for the three persons of the Trinity. In Rublev’s representation of the scene, the three gold-winged figures are seated around a white table on which a golden, chalice-like bowl contains a roasted lamb. In the background of the picture, a house can be seen at the top left and a tree in the center. Less distinctly, a rocky hill lies in the upper right corner. The composition is a great circle around the table, focusing the attention on the chalice-bowl at the center, which reminds the viewer inescapably of an altar at Communion.
On one level this picture shows three angels seated under Abraham’s tree, but on another it is a visual expression of what the Trinity means, what is the nature of God, and how we approach him. Reading the picture from left to right, we see the Father, the Son, and the Holy Spirit.
Each person holds a staff, which is so long it, cuts the picture into sections. Why should beings with wings, that can fly like the light, have need of a staff for their journey? Because we are on a journey and these three persons enter into our journey, our slow movement across the face of the earth. Their feet are tired from traveling.
God is with us in the weariness of our human road. The traveler God sits down at our ordinary tables and spreads them with a hint of heaven.
The Table
The table or altar lies at the center of the picture. It is at once the place of Abraham’s hospitality to the angels, and God’s place of hospitality to us. That ambiguity lies at the heart of communion, at the heart of worship. As soon as we open a sacred place for God to enter, for God to be welcomed and adored, it becomes his place. It is we who are welcomed, it is we who must ‘take off our shoes’ because of the holiness of the ground.
Contained in the center of the circle, a sign of death. The lamb, killed. The holy meal brought to the table. All points to this space, this mystery: within it, everything about God is summed up and expressed, his power, his glory, and above all his love. And it is expressed in such a way that we can reach it. For the space at this table is on our side. We are invited to join the group at the table and receive the heart of their being for ourselves.
We are invited to complete the circle, to join the dance, to complete the movements of God in the world by our own response. It lies before us. It invites us to come into the depth and intimacy of all that is represented here in the Holy Trinity.  
The invitation is to each of us today…..

Come follow the Spirit up the hill of prayer.

Come, live in the shadow of the Son of God,

rest yourself beneath his tree of life. 

Come, journey to the home, prepared for you in the house of your Father.

Here…..The table is spread, the door is open. Come.”

Taken from. 

(http://www.sacredheartpullman.org/Icon%20explanation.htm)
All-Holy Trinity, have mercy on us.

Lord, cleanse us.

Master, pardon us.

Holy God, visit and heal us

For Thy Name’s sake. Amen.