The collect for today, the Octave Day of Pentecost, commonly called Trinity Sunday, from The Book of Common Prayer (Canadian, 1962):
ALMIGHTY and everlasting God, who hast given unto us thy servants grace, by the confession of a true faith, to acknowledge the glory of the eternal Trinity, and in the power of the Divine Majesty to worship the Unity: We beseech thee, that this holy faith may evermore be our defence against all adversities; who livest and reignest, one God, world without end. Amen.
The Lesson: Revelation 4:1-11
The Gospel: St. John 3:1-15
Artwork: Guido Reni, Holy Trinity, 1625. Oil on canvas, Chiesa della Santissima Trinità dei Pellegrini, Rome.