Muhammad uses the local idioms of his culture in his Koran, thus showing that his Koran comes from him, his friends and scribes, not from a real god.
On An Edge
Another local idiom I noticed recently is this:
22:11 And of the people is he who worships Allah on an edge.
If he is touched by good, he is reassured by it; but if he is struck by trial, he turns on his face [to the other direction].
He has lost [this] world and the Hereafter. That is what is the manifest loss.
Koran 22:11
Notice “on an edge” is a local idiom, used nowhere else in the Koran.
Stamp Their Feet
In this verse, Muhammad refers to women in bare feet with a string of bells around the ankle, stamping their feet to advertise their “availability”. This is prostitution.
And let them not stamp their feet to make known what they conceal of their adornment.
Excerpt, Koran 24:31
This is obviously very local.
Emotional Nail-Biting
Another idiom I found is what seems to be nail-biting:
Here you are loving them but they are not loving you, while you believe in the Scripture – all of it. And when they meet you, they say, “We believe.”
But when they are alone, they bite their fingertips at you in rage.
Say, “Die in your rage. Indeed, Allāh is Knowing of that within the breasts.”
Koran 3:119
And the Day the wrongdoer will bite on his hands [in regret] he will say, “Oh, I wish I had taken with the Messenger a way.
Koran 25:27
I suspect that Muhammad bit his nails, emotionally, when enraged or nervous.
Conclusion
Muhammad was a false prophet, for a false god, Allah, for a false religion, Islam, without even a false book, the Koran.
Koran Contradiction 