Started on Gogol, already confused

UPDATE: In retrospect, I suppose the Russian role in the Greek Revolution wasn't that small, and then one considers the Russo-Turkish war immediately following it, so I suppose it makes sense that some provinicial who had some sort of military service could for some reason have paintings of figures from the Greek Revolution around the house. It's odd, but not incomprehensible.

I started on Gogol's Dead Souls because it quite fortunately arrived in the 12/31/07 post, but I am already slightly confused one of the characters. Mikhail Semyonovich Sobakevich (last name, of course, derived from "dog") is portrayed as being a bear whose furniture is essentially miniature versions of himself. What is incomprehensible: why does he have all those paintings of figures from the Greek Revolution? It seems rather random, despite the Russian involvement in the revolution. I have no problem with nonsense and randomness, but usually there is either some possible thread tying it together or it is completely nonsensical; what is hard to endure is something that may have some sense behind it which I cannot understand yet.

For Thou art our God and we know no other than Thee

Having beheld the Resurrection of Christ, let us worship, the holy Lord Jesus, the only Sinless One! We venerate Thy Cross, O Christ, and Thy Holy Resurrection we praise and glorify; for Thou art our God, and we know no other than Thee; we call on Thy name. Come, all you faithful, let us venerate Christ's Holy Resurrection! For, behold, through the Cross joy has come into all the world. Let us ever bless the Lord, praising His Resurrection. By enduring the Cross for us, He destroyed death by death!

The phrase in the title has been sticking in my head lately. It feels like it should come from the Psalms or at least something in the Scriptures, but I cannot quite find the reference. All my googling seems to turn up is this above hymn to the Resurrection and various other Orthodox sources which are clearly derivative. Even as vague a search as "you are our god" "know no other" (or with "Thou" appropriately substituted) does not have much luck. So, help on sources for this phrase (if any exist) would be appreciated. Obviously, the sentiment is found all over the Old Testament since it is the major theme of the work, but I want to find it expressed with these phrases in close proximity or in similar words.