Thus saith the Lord. Joshua began his speech in the solemn form used by the prophets and introduced God Himself as speaking in His own person. It would seem from this that Joshua was a prophet as well as a ruler.
Flood. Heb. nahar, “river.” The reference is to the Euphrates River, by the waters of which lay Ur of the Chaldees.
Served other gods. Joshua bade the people remember that their forefathers had been idolaters such as the Israelites were now exterminating. It was only by the grace of God that the Israelites were now in such a favored state. There was great danger that they would forget the rock from whence they were hewn and lapse back into idolatry.