In the following short video the man Muslims take to be the best example for mankind is shown to have had quite a foul mouth on him. In fact, as you will see, at least one prominent Muslim has the "testicular fortitude" (one of his favorite phrases) to virtually admit this to have been the case.
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For more evidence that Muhammad did not have control over his own tongue and was thus far from "the best of men," see the following articles:
Muhammad - The Cruel and Abusive Prophet
Watching Snow Fall in Summer