What does Isaiah 11:15 mean?
This chapter has been describing the future kingdom of the Messiah. One aspect of this kingdom will be that the Lord will bring together all the scattered people of Israel and Judah (Isaiah 11:11–12). They will be reunited as one people under the Messiah. And as one nation they will defeat all their regional enemies. They will reclaim the Promised Land, and bring lasting peace to the region.Now the prophet Isaiah backs up a bit to describe how the people will be able to return to the land. He pictures the Sea of Egypt, also known as the Red Sea, and the Euphrates river as obstacles. These two bodies of water stand in the way of the return of some of the Israelites. To give His people safe passage, the Lord will do something similar as when he gave them an escape route out of Egypt during the exodus.
For that reason, the Lord will destroy the "tongue", a bay or gulf, of the Red Sea. In other words, He will cause the water to disappear in some way from that body of water to make it possible to cross over. Next, the Lord will wave His hand over the great Euphrates River and use His scorching hot wind to create seven crossing points over which people can walk across even in sandals.
This is all hard to imagine, but Isaiah's point is not. The same God who freed His people during the exodus will once again free His people. And He will make a way for them to return to the Promised Land. No "impossible" obstacles will stand in His way of keeping this promise to His people.