Read your history. Pre-Assad Syria was no friend of Israel's. Read about the 1,000s of Syrian Jews who had there property expropriated and killed in pogroms and eventually chased out in the 1940s.
ISIS kills 22 in Yemen's Sanaa, Aden; targets both gov't and Houthi rebels (Reuters)
from the article: For first time since Yom Kippur War: Israel fires warning shot at Syria