What does Isaiah 17:3 mean?
This oracle from the Lord is about Damascus and Aram—Syria—but now Isaiah widens it to include Aram's close ally at the time: Israel. All of Isaiah's prophecies were written primarily for God's people. Though many are "about" other nations, they are not meant as messages to those people. Rather, the Lord wanted His people in Israel and Judah to understand that He was the Lord of all the world. He wanted them to understand His power over all the nations. His first desire for the house of Jacob was to trust in Him alone, instead of turning to other nations or their gods for protection.During this time, Assyria had become a major power intent on controlling as much of the world as they could. In attempting to resist Assyria, the Syrians made an alliance with Israel. Israel at that time would have consisted of the northern ten tribes of God's people (1 Kings 12:16–20). Together, Israel and Syria had attempted to get Judah to ally with them against the Assyrians. Instead, King Ahaz of Judah made an alliance with the Assyrians. That's when Israel and Syria attacked Judah to try and replace Ahaz as king.
In chapter 7, the Lord sends Isaiah to Ahaz to tell him not to fear the kings of Israel and Syria because their plan was going to fail. "It shall not stand, and it shall not come to pass (Isaiah 7:7)." That prophecy to the anxious King Ahaz fits with this oracle against Damascus. Ephraim was another name for Israel because it was the largest of the northern ten tribes. The disappearance of "the fortress" meant that Israel would lose the ability to defend itself. The loss of "the kingdom" from Damascus meant that Syria would lose its authority as ruler over its people and territories. Both prophecies were fulfilled when the Assyrians decimated Syria and Israel in 732 BC.
Isaiah shows that the fates of both nations are connected. The survivors in Syria will have the same level of power and authority as the children of Israel at that time, which will be very little. The prophet reminds his readers this declaration comes from the Lord of hosts. He is the One who will bring this judgment on both Israel and Syria, using the Assyrians as the tool to do it.