Negative commandment · Lo Ta’aseh #358 of 613
For a rapist not to divorce the woman he raped
שלא יגרש האונס אנוסתו
The verse · Devarim 22:29
וְנָתַן הָאִישׁ הַשֹּׁכֵב עִמָּהּ לַאֲבִי הַנַּעֲרָ חֲמִשִּׁים כָּסֶף וְלוֹ־תִהְיֶה לְאִשָּׁה תַּחַת אֲשֶׁר עִנָּהּ לֹא־יוּכַל שַׁלְּחָהּ כׇּל־יָמָיו
“then the man that lay with her shall give to the girl’s father fifty shekels of silver, and she shall be his wife; because he has humbled her, he may not put her away all his days.”
The Rambam’s words
For a rapist not to divorce the woman he raped, as [Deuteronomy 22:29] states: "He may not send her away for his entire life."
שלא יגרש האונס אנוסתו, שנאמר "לא יוכל שלחה, כל ימיו" (דברים כב,כט).
Why · Sefer HaChinuch #558
That he not divorce her all of his days
“It is from the roots of this commandment [that it is] in order to restrain the villains from this evil deed, and that the daughters of Israel should not be as if abandoned.”
Where in the Mishneh Torah
Hilchot Virgin Maiden הלכות נערה בתולה