Probably a Syrian missile had accidentally landed in the north of the Golan Heights [Syrian, occupied by Israel since 1967] instead of its target, opponents of the Syrian government. The missile did not result in any injuries or damage.
The Israeli armed forces have often beaten back when Syrian rockets ended up across the border. A Syrian military spokesman claimed on state television that Israel with this attack helps Islamist rebels against the Assad government. Israel has so far steered clear of the civil war in Syria.
This Israeli retaliation for that Syrian mistake killed four Syrians.
The Israeli government earlier on had been more clever than the Turkish government; when a Russian aircraft accidentally flew through Israeli airspace, they did not shoot it down. While the Turkish government had a Russian airplane shot down.
There is already Syrian government violence and jihadi violence in Syria. US American, Russian, German, British, Dutch, etc. war planes drop bombs on Syria. We deed not any more warplanes, whether from Israel or anywhere else.