Temurah 5A

מיתיבי: אונס שגירש, אם ישראל הוא ⁠— מחזיר ואינו לוקה, ואי אמרת כיון דעבר אמימרא דרחמנא לקי, הא נמי לילקי! תיובתא דרבא.

The Talmud raises an objection from a baraita: With regard to a rapist who married and then divorced his victim, if he is an Israelite, who is permitted to marry a divorcée, he remarries her and he is not flogged. And if you say, like Rava, that since one violates the statement of God, he is flogged, this one should be flogged as well for divorcing his victim. But according to the opinion of Abaye, it stands to reason that he should not be flogged, since his remarriage nullifies the effects of the divorce. This should be a conclusive refutation of the opinion of Rava.

אמר לך: שאני התם, דאמר קרא ״כל ימיו״, כל ימיו בעמוד והחזיר.

The Talmud answers that Rava could say to you: It is different there, as the verse states: “He may not send her away all his days” (Deuteronomy 22:29). This teaches that for all his days, he remains under the obligation to arise and remarry her. Once he remarries her, it turns out that he did not divorce her for all of his days and therefore did not violate the prohibition. This is why he is not flogged.

ולאביי, אי לאו דאמר רחמנא ״כל ימיו״, הוה אמינא איסורא הוא דעבד ליה, אי בעי ליהדר ואי בעי לא ליהדר, קא משמע לן.

The Talmud asks: And according to the opinion of Abaye, what is derived from the phrase “all his days”? The Talmud answers: If God did not state “all his days,” I would say that he has violated a prohibition by divorcing her, and that if he desires he may choose to remarry her, and if he so desires he may choose not to remarry her. The phrase “all his days” teaches us that he is obligated to remarry her.