When it is said
It closes the prayers before sleep in the Russian prayer book, said while making the sign of the cross.
St Tikhon’s prayer book of 1982 asks the reader to kiss their cross first. Then the reader makes the sign of the cross over the bed, from head to foot and from side to side, while saying it.
Orthodox Christians also turn to it at any hour: when doubts or temptations come, when they are suddenly afraid, or in danger.
The Russian prayer book gives a one-line form too: “Protect me, O Lord, by the power of Your precious and life-giving Cross, and keep me from all evil.”
Where it comes from
No author known
How old is it?
The prayer books give no author. Hieromonk Dalmat (Yudin) has traced the prayers before sleep in old Russian books. He finds this prayer in a Psalter copied in Moscow in 1507. There it already comes at the end of the prayers before sleep, as it does today. Moscow’s first edition of the Psalter with its added prayers, printed in 1625, has it too.
Hieromonk Dalmat (Yudin), on the history of the prayers before sleep (Azbyka.ru)
Psalm 68, and Easter
Its first lines are the opening of Psalm 68 (67 in the Greek and Slavonic Bibles). They go back to Numbers 10:35, the words Moses said whenever the ark set out. The Russian prayer book’s note says the Fathers read “Let God arise” as David foretelling Christ’s resurrection. The Church sings the same verse at Easter, with the hymns of Pascha.
Azbyka.ru, the prayer to the Precious Cross; Azbyka.ru, the prayers before sleep; G. V. Shann, Euchology (1891), the Easter hymns
What the words mean
Why speak to a Cross?
The prayer speaks to the Cross and tells it to rejoice, the way Isaiah speaks to the heavens and calls on them to rejoice. A Russian Orthodox guide to the prayer explains: a prayer to Christ’s Cross rises to the One crucified on it, and the help comes from the Lord Himself. St John of Damascus, in his summary of the Orthodox faith, said Christians honour the Cross as a sign of Christ, “not honouring the tree”.
Azbyka.ru, the prayer to the Precious Cross; St John of Damascus, An Exposition of the Orthodox Faith, Book 4, chapter 11
A sign of a victory won
St John of Damascus also called the Cross “the shield and weapon against, and trophy over, the devil”. A trophy marks a battle already won. The prayer says the same: Christ went down to Hades, trampled on the devil’s power, and gave us His Cross. That is why the prayer greets the Cross with “Rejoice”.
St John of Damascus, An Exposition of the Orthodox Faith, Book 4, chapter 11
The Scripture in it
God arises. His enemies are scattered, and those who hate Him flee His presence. As smoke is blown away, You will drive them out; as wax melts before the fire, the wicked will perish in the presence of God.
Whenever the ark set out, Moses would say, “Rise up, O LORD! May Your enemies be scattered; may those who hate You flee before You.”
Now since the children have flesh and blood, He too shared in their humanity, so that by His death He might destroy him who holds the power of death, that is, the devil …
Bible text: Berean Standard Bible, public domain.
In Church Slavonic
Да воскреснет Бог, и расточатся врази Его, и да бежат от лица Его ненавидящии Его.
Яко исчезает дым, да исчезнут; яко тает воск от лица огня, тако да погибнут беси от лица любящих Бога и знаменующихся крестным знамением, и в веселии глаголющих:
радуйся, Пречестный и Животворящий Кресте Господень, прогоняяй бесы силою на тебе пропятаго Господа нашего Иисуса Христа, во ад сшедшаго и поправшего силу диаволю, и даровавшаго нам тебе Крест Свой Честный на прогнание всякаго супостата.
О, Пречестный и Животворящий Кресте Господень! Помогай ми со Святою Госпожею Девою Богородицею и со всеми святыми во веки. Аминь.
From the prayers before sleep in the Russian prayer book, on Azbyka.ru, a Russian Orthodox website.