The media, as is its usual wont, is mistranslating the Muslim terrorist's cry of, "Allahu Akbar" as he opened fire at a Christmas market in France.
It does not mean "God is great".
Translating Allah as God is fundamentally misleading because Islam is a very different religion than Christianity or Judaism. And its "god" is of a very different character and nature.
The false sense of familiarity, the misleading notion that Islam is just another "Abrahamic" religion (a silly and meaningless term), helps insulate us from understanding the real threat or addressing the problem.
But Allahu Akbar also does not mean merely that Allah is great, but greater. It is a statement of supremacism over non-Muslims.
It's a message of violence and hatred that originated with Mohammed's original genocide of the Jews.
"Allahu Akbar" meant, when Mohammed first said it, "I'm going to kill you."
That's what it means.
Islam believes that violence proves the power of Allah. When Muslims kill non-Muslims, as Mohammed did the Jews, or as Cherif Chekatt killed shoppers at a Christmas market in Strasbourg, this testifies to the truth of Allah and Islam.
"Allahu Akbar" means "I'm going to kill you."
So does Islam.