Isa 17:1 An oracle concerning Damascus. Behold, Damascus will cease to be a city and will become a heap of ruins.
Isa 17:2 The cities of Aroer are deserted; they will be for flocks, which will lie down, and none will make them afraid.
Isa 17:3 The fortress will disappear from Ephraim, and the kingdom from Damascus; and the remnant of Syria will be like the glory of the children of Israel, declares the LORD of hosts.
Verse 3 shows that this prophecy has already been fulfilled because Syria becomes like the glory of Israel ie; fading away as Israel was at that time in the northern kingdom (Ephraim).
The Keil and Delitcsh commentary has this to say:-
Damascus is removed îòéø (= òéø îäéåú, cf., 1Ki_15:13), i.e., out of the sphere of existence as a city. It becomes îòé, a heap of ruins. The word is used intentionally instead of òé, to sound as much as possible like îòéø: a mutilated city, so to speak. It is just the same with Israel, which has made itself an appendage of Damascus.
When we speak of something being in ruins, it is often poetical language as it is here. The city of Damascus as a force to be reckoned with had ceased, this is the thrust of the passage.
There are prophecy commentators out there who are misleading believers by suggesting that present day Damascus is about to be blitzed based on this scripture. If I am not mistaken, a certain Tim McHyde (escape all these things.com) is one of them and I would warn believers to take great care with what he teaches/states as it is extreme and unbalanced in my view. For instance, he states that the beast in revelation is a second Babylon. While I clearly demonstrated to him the error of this, he effectively shut his ears and would not listen to sound reason.
Hope this shines some light on this scripture.
Richard Spendiff