The attackers of Charlie Hedbo claimed Allah's name had to be avenged.
Why can't Allah do the job himself?
It reminds me of the Old Testament story of Elijah and the Prophets of Baal.
Elijah let them go first - build an altar and have Baal rain down fire.
They worked hard all day long, and nothing happened.
It came about at noon, that Elijah mocked them and said, “Call out with a loud voice, for he is a god; either he is occupied or gone aside, or is on a journey, or perhaps he is asleep and needs to be awakened.” 28 So they cried with a loud voice and cut themselves according to their custom with swords and lances until the blood gushed out on them. 29 When midday was past, they [n]raved until the time of the offering of the evening sacrifice; but there was no voice, no one answered, and no [o]one paid attention.
Elijah built his altar and made God's job tougher. He filled the area with water before asking for fire.
38 Then the fire of the Lord fell and consumed the burnt offering and the wood and the stones and the dust, and licked up the water that was in the trench.
The people who watched Elijah found out who God really is.