And if the LORD thy God enlarge thy coast, as he hath sworn unto thy fathers, and give thee all the land which he promised to give unto thy fathers;
And if the Lord ... enlarge thy coast. Three additional sanctuaries were to be established in the event of their territory extending over the country from Hermon and Gilead to the Euphrates (see the notes at Genesis 15:18; Exodus 23:31). But it was obscurely hinted that this last provision would never be carried into effect, as the Israelites could not fulfill the conditions-namely, 'that of keeping the commandments, to love the Lord, and walk ever in his ways.'
In point of fact, although that region was brought into subjection by David and Solomon, we do not find that cities of refuge were established, because those sovereigns only made the ancient inhabitants tributary, instead of sending a colony of Israelites to possess it. The privilege of sanctuary cities, however, was given only for Israelites; and besides, that conquered territory did not remain long under the power of the Hebrew kings.
One of the arguments of the modern Jews for concluding that Messiah is yet to come is founded on this passage-that as there was an addition of three cities of refuge in ancient times, the promise still remains to be fulfilled; because God never commanded a thing in vain (extract from Treatise of Maimonides in Wolff's 'Journal,' p. 58).