The Ferengi idea that the universe is a great river of supply and demand, carrying goods from those who have to those who want, which a skilled trader can navigate.
The Great Material Continuum is how Ferengi picture the economy of the universe. There are millions of worlds, each with too much of one thing and too little of another. The Continuum flows between them like a river, and whoever steers it wisely will have everything they desire.
Nog explains the belief in Treachery, Faith and the Great River in 2375. Miles O'Brien has been ordered to obtain a graviton stabiliser for the Defiant in three days, although supply channels say it will take weeks. Nog takes over and begins a chain of trades that includes lending Benjamin Sisko's desk and Martok's bloodwine to other parties.
O'Brien expects a court martial as the deals grow more tangled. Nog tells him to have faith, and the river provides. The part arrives on time and everything borrowed is returned.