This is a sheet music from Orthodox liturgy. It was composed by the concertist and composer Boris Petrov. Those two unaccompanied chorus end the oratorio “Transfiguration.” It is intended for mixed choirs, two soloists (soprano and baritone) and symphony orchestras. It is divided into 9 spiritual movements beautifully written. The choir has an important place. This sheet music is perfect for the voices, but you can also do a series of chords or add some imitation sections. Psalmody is the birth of Orthodox singing before harmonic times. This oratorio was written during the 80’s in USSR. It was intended for sacred music and was not played before January 1995 in Moscow Conservatory. It was praised by Russian music criticism. A critique wrote that “that evening, people wept with joy and emotion.” Several extracts were used in Russian movies like “Milocerdia” and “Gospodi.” Boris Petrov was born in Bakou, USSR, in 1955. Since he was 10, he studied at Moscow school of music. Then he studied at Moscow Conservatory.