The holy right-believing sovereign Emperor Justinian devoted much attention and effort to the struggle with Origenists of his time, who then were reviving the Nestorian heresy. To counter their heretical speculations, the Church hymn "Only-Begotten Son and Immortal Word of God, Who for our salvation..." was composed. Emperor Justinian commanded that the hymn be sung in all the churches. This hymn is sung at the Divine Liturgy before the Small Entrance after the second Antiphon from that time to the present day.
- Only Begotten Son and Immortal Word of God,
- Who for our salvation didst will to be incarnate of the holy Theotokos and ever virgin Mary,
- Who without change didst become man and wast crucified, O Christ our God,
- Trampling down death by death, Who art one of the Holy Trinity,
- Glorified with the Father and the Holy Spirit, save us.
The hymn is very theological, composed in honor of the incarnate Jesus Christ. The hymn also served to clearly respond to multiple heresies that plagued the Church such as the meaning of the incarnation, changelessness of God, resurrection, Trinitarian theology. It sets forth the Orthodox teaching on the Second Person of the Trinity. He being the Only-begotten (one in essence) Son and Word of God, being immortal, became man, without ceasing to be God, and accepted a human body from the Holy Theotokos and ever virgin Mary. By his crucifixion, he with his death conquered death, "trampling down death by death," as one of the three Persons of the Holy Trinity, and is glorified equally with the Father and the Holy Spirit.
The hymn praises the true God as he revealed himself to be, and as he has offered salvation to mankind.