Adam Clarke on Exodus 23:31

I will set thy bounds from the Red Sea - On the south-east, even unto the sea of the Philistines - the Mediterranean, on the north-west; and from the desert - of Arabia, or the wilderness of Shur, on the west, to the river - the Euphrates, on the north-east. Or in general terms, from the Euphrates on the east, to the Mediterranean Sea on the west; and from Mount Libanus on the north, to the Red Sea and the Nile on the south. This promise was not completely fulfilled till the days of David and Solomon. The general disobedience of the people before this time prevented a more speedy accomplishment; and their disobedience afterwards caused them to lose the possession. So, though all the promises of God are Yea and Amen, yet they are fulfilled but to a few, because men are slow of heart to believe; and the blessings of providence and grace are taken away from several because of their unfaithfulness.