When it is said
The choir sings it near the start of the Orthodox service of thanksgiving for an answered prayer.
The translator Isabel Hapgood’s service book of 1906 also gives it at the thanksgiving for the New Year and at the Te Deum, the great service of thanksgiving.
At home it can be said whenever you want to thank God.
Where it comes from
No author known
A hymn from the Russian service books
A troparion is a short hymn. This one is sung at the service of thanksgiving for an answer to prayer and for every favor from God. No one knows who wrote it. Hapgood translated it in 1906 from the Church Slavonic service books of the Russian Church.
Isabel F. Hapgood, Service Book of the Holy Orthodox-Catholic Apostolic Church (1906), page 515
In the home prayer book
Russian prayer books print the hymn under the heading “Thanksgiving for every benefit of God”, among the prayers people say at home. A note there says it comes from the Church’s service of thanksgiving for an answered prayer.
Благодарение за всякое благодеяние Божие (Azbyka.ru prayer book)
The Scripture in it
“So you also, when you have done everything commanded of you, should say, ‘We are unworthy servants; we have only done our duty.’”
Bible text: Berean Standard Bible, public domain.
In Church Slavonic
Благода́рни су́ще недосто́йнии раби́ Твои́, Го́споди,
о Твои́х вели́ких благодея́ниих, на нас бы́вших,
сла́вяще Тя хва́лим, благослови́м, благодари́м,
пое́м и велича́ем Твое́ благоутро́бие,
и ра́бски любо́вию вопие́м Ти:
Благоде́телю Спа́се наш, сла́ва Тебе́.
From the Russian prayer book on Azbyka.ru, “Thanksgiving for every benefit of God”, troparion in tone 4.