I believe this is a mistranslation. I believe the phrase means: "Allah is greater".
It is a direct challenge to other religions. My god is greater than your god. This puts the lie to the concept that "We all worship the same being". No. Moslems don't see it that way (and neither do I). There is Jehovah and there is Allah. They are in opposition. And the Muslims say that Allah is greater than Jehovah.
And, to prove it, they set themselves on fire and die screaming. Then they go to Hell and discuss the matter with Satan (AKA Allah).
It can also be legitimately translated as "Healthcare for all!" and "Resist Trump!"
George Bush claimed to be a Christian. Yet he said Muslims and Christians pray to the same God. He also said Jesus was a man. Obviously, Mr Bush does not know the Bible.
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