So the people shouted, and [the priests] blew the trumpets; and it happened, when the people heard the sound of the trumpet, that the people shouted with a great shout, and the wall fell down flat, so that the people went up into the city, every man straight before him, and they took the city.
Now how did Joshua know that? It didn't happen for several hundred years, but you will read in first Kings, the sixteenth chapter, and the thirty-fourth verse where the king decided to rebuild the city of Jericho, and they started building it in the time of his firstborn son. Then when his youngest son was born, they set the gate of the city of Jericho. The prophecy here of Joshua was literally fulfilled. The man was cursed also, so the whole prophecy was fulfilled. "