25. The object is to impress the point that the Prophet (peace be upon him) has no authority whatsoever to make any change in the revelation. If he did so, he would be severely punished. The style depicts the prompt and quick action of a king who strikes off the head of an official, holding him by the hand, if he commits a forgery in his name. Some people have misconstrued this verse to mean that if the heart-vein or neck-vein of an impostor is not immediately severed by Allah, it would be a proof that he was a true prophet, whereas in this verse what has been said is about a true prophet and not about the impostors. Same impostors have even claimed to be God and have thrived and lived long lives in the world, so it could not be a proof of the truth of their claim. For a full discussion of this question, see( E.N. 23 of Surah Younus).