The Literal Commandment
If any man takes a wife and goes in to her and then turns against her, and charges her with shameful deeds and publicly defames her, and says, 'I took this woman, but when I came near her, I did not find her a virgin,' then the girl's father and her mother shall take and bring out the evidence of the girl's virginity to the elders of the city at the gate. The girl's father shall say to the elders, 'I gave my daughter to this man for a wife, but he turned against her; and behold, he has charged her with shameful deeds, saying, "I did not find your daughter a virgin." But this is the evidence of my daughter's virginity.' And they shall spread the garment before the elders of the city. So the elders of that city shall take the man and chastise him, and they shall fine him a hundred shekels of silver and give it to the girl's father, because he publicly defamed a virgin of Israel. And she shall remain his wife; he cannot divorce her all his days.(Deuteronomy 22:13-19)
The literal commandment is that a man who turns against his wife and falsely accuses her of adultery is forbidden to divorce her.