Exodus 21:3

אם בגפו יבא IF HE CAME IN BY HIMSELF — This means that he was unmarried — as the Targum renders it אם בלחודוהי, if he came in “alone”. The term בגפו is the same as גף) בכנפו being synonymous with כנף wing, skirt) i. e. he came in only just as he was, alone, merely wrapped in his garment: so that בגפו, “in his skirt”, means “in the skirt of his garment”. בגפו יצא HE SHALL GO OUT BY HIMSELF — This intimates that if he was unmarried originally (when he came in), his master is not allowed to give him against his will a Canaanitish handmaid with the object of raising slaves (Kiddushin 20a). אם בעל אשה הוא IF HE BE MARRIED to an Israelite woman (Mekhilta), ויצאה אשתו עמו then HIS WIFE SHALL GO OUT WITH HIM — But who brought her in (into the state of service) that the text has to state she shall go out? But by saying this Scripture intimates that he who acquires a Hebrew servant is bound to provide his wife and children also with food (Mekhilta; Kiddushin 22a).

אִם־בְּגַפּ֥וֹ יָבֹ֖א בְּגַפּ֣וֹ יֵצֵ֑א אִם־בַּ֤עַל אִשָּׁה֙ ה֔וּא וְיָצְאָ֥ה אִשְׁתּ֖וֹ עִמּֽוֹ׃

If he came in by himself, he shall go out by himself: if he is married, then his wife shall go out with him.