These are the Days of Awe, the intermediate days between Rosh Hashanah and Yom Kippur, when Jews believe God is judging us for our behavior over the past year. I am not a great expert on what God does or doesn't do, or when He does it, nor am I a great expert on the Jewish law governing this period, but I'm pretty sure that burning down a mosque violates the letter and spirit of said law, and doing so during the Days of Awe puts the arsonist's soul in eternal danger. Like I said, I'm pretty sure about this one. Which means that the barbarians who sacked a mosque in the Galilee better start hiding from God. Which is, of course, impossible, but it's the only advice I could think of, other than asking them to repent for their sin, which I'm sure they don't think of as a sin, in any case.
UPDATE: Condemnations of this terrible act are pouring in from all corners of the Jewish world, thank God:
Jerusalem - Chief Rabbi of Israel Yona Metzger accompanied President Shimon Peres for a visit to the Tuba Zangaria mosque torched overnight during a "Price Tag" operation.
"We remember when our books were burnt and we cannot abide such actions against any other religion. For us - a synagogue, a mosque, a church - they are considered embassies of God, and you do not harm embassies," said Metzger.