It is Truly Meet (Достойно Есть) by Kurt Sander (Курт Сандер)

Canticum Festum - Liubov Shangina, conductor from the CD: Liturgy in Church Slavonic on Orthodox Recordings. Streaming on all platforms TRANSLATION Dostoino Est’ (It is Truly Meet) It is truly meet to bless thee, O Theotokos (Birth-giver of God) Ever-blessed and most pure, and the Mother of our God. More honorable than the Cherubim, and beyond compare more glorious than the Seraphim Without corruption thou gavest birth to God, the Word True Theotokos, we magnify thee.