Eternal Threefold Exchanges

When Christ, the most high Lord, comes down
   from the heavens,
The brightest sign and standard of the Cross
   will shine forth.
The two principal lights being obscured,
The stars will fall to earth like the fruit of a fig
   tree
And the face of the world will be like the fire of
   a furnace
By the singing of hymns eagerly ringing out,
By thousands of angels rejoicing in holy
   dances,
And by the four living creatures full of eyes,
With the twenty- four joyful elders
Casting their crowns under the feet of the
   Lamb of God,
The Trinity is praised in eternal threefold
   exchanges.

The Altus Prosator, by St. Columba

From The Path of Celtic Prayer: An Ancient Way to Everyday Joy, by Calvin Miller