Canon of the feast, with 8 troparia, including its irmos, the composition of Cosmas, in Tone IV—
Speaking words of life and giving instruction concerning that which is divine, Christ said to his friends: “Recognize the Father in Me, for I emit unapproachable light, unto the joy of those who chant: Let us sing unto our God, for He hath been glorified!”
Irmos: The people of Israel, having fled across the watery deep of the Red Sea with dryshod feet, beholding the mounted captains of the enemy drowned therein, sang with gladness: Let us chant unto our God, for He hath been glorified!
“Ye will be invested with the power of tongues, O My friends and disciples, and will be marvelous in the richness thereof, for ye will be filled with glory. For I shall reveal Myself to be brighter than the sun, illumining those who chant in joy: Let us sing unto our God, for He hath been glorified!”
Shining forth today with divine radiance on Mount Tabor, as He promised, Christ hath laid bare His countenance to His disciples. And, full of light-bearing and divine splendor, they chanted in joy: Let us sing unto our God, for He hath been glorified!
Translated by Isaac Lambertsen. Edition menaion.en.lambertsen.