Cows have two intestines but four stomachs (one stomach with four digestive departments). So if the Prophet said that humans had seven intestines, then the prophet must be right. If Humans only have two intestines—the small intestine and the large intestine—then the prophet must be wrong.
The Bible says that when prophets speak untruth that they are not to be followed.
“The Lord your God will raise up for you a prophet like me from among you, from your brethren—him you shall heed— just as you desired of the Lord your God at Horeb on the day of the assembly, when you said, ‘Let me not hear again the voice of the Lord my God, or see this great fire any more, lest I die.’ And the Lord said to me, ‘They have rightly said all that they have spoken. I will raise up for them a prophet like you from among their brethren; and I will put my words in his mouth, and he shall speak to them all that I command him. And whoever will not give heed to my words which he shall speak in my name, I myself will require it of him.
But the prophet who presumes to speak a word in my name which I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die.’ And if you say in your heart, ‘How may we know the word which the Lord has not spoken?’—when a prophet speaks in the name of the Lord, if the word does not come to pass or come true, that is a word which the Lord has not spoken; the prophet has spoken it presumptuously, you need not be afraid of him. (Deuteronomy 18:15–22)
“If a prophet arises among you, or a dreamer of dreams, and gives you a sign or a wonder, and the sign or wonder which he tells you comes to pass, and if he says, ‘Let us go after other gods,’ which you have not known, ‘and let us serve them,’ you shall not listen to the words of that prophet or to that dreamer of dreams; for the Lord your God is testing you, to know whether you love the Lord your God with all your heart and with all your soul. (Deuteronomy 13:1–3)The Truth Is A Matter Of Whether A Person Desires Honesty And Freedom From Sin