Commentary for Kiddushin 31:14

A female Jewish slave goes free when she hits puberty. But a girl does not automatically leave her father’s authority at puberty—she must also be at least 12 years old. So Resh Lakish argues that it is easier to leave the master’s authority than to leave her father’s authority. And if she leaves her father’s authority upon her father’s death (meaning she can now keep her own handiwork), so too she must leave her master’s authority upon her father’s death, even though she is no longer living with her father.