פירוש על קידושין 36:1

The Torah states that if he did not designate her to his son as a wife or marry her himself, he must set her free. He cannot sell her to non-Jews. The phrase used for “deal deceitfully” is “bevigdo bah.” Beged (bg”d) is the root for “dealing deceitfully” but it is also the root for the word “clothing.” R. Akiva reads the word as if it means “clothing”—once the master has “spread his clothing over her,” i.e. he has married her, can no longer sell her. Once she was married, the father can no longer sell her. R. Eliezer reads the word differently—since the father dealt deceitfully with her by selling her the first time, he can no longer sell her.