They served other gods - Possibly the "images," or teraphim, which we find their ancestor Laban calling "his gods" (see the marginal reference); and of which it would seem that there were, as Joshua spoke, some secret devotees among the people Joshua 24:14, Joshua 24:25. It is not stated that Abraham himself was an idolater, though his fathers were. Jewish tradition asserts that Abraham while in Ur of the Chaldees was persecuted for his abhorrence of idolatry, and hence, was called away by God from his native land. The reference in the text to the original state of those who were the forefathers of the nation, is made to show that they were no better than others: God chose them not for their excellences but of His own mere motion.

and you came unto the sea; which respects some senior persons then present; for, besides Caleb and Joshua, there were many at this time alive who came to and passed through the Red sea, at their coming out of Egypt; for those whose carcasses fell in the wilderness were such as were mere than twenty years of age at their coming out from Egypt, and who were the murmurers in the wilderness; and it may be reasonably supposed, that many of those who were under twenty years of age at that time were now living:

and the Egyptians pursued after your fathers, with chariots and horsemen, into the Red sea; of the number of their chariots and horsemen, see Exodus 14:7; with these they pursued the Israelites, not only unto, but into the Red sea, following them into it; the reason of which strange action is given in Joshua 24:7.