Rashi on Genesis 34:1/רש"י על בראשית ל״ד:א׳

1בת לאה THE DAUGHTER OF LEAH — so Scripture calls her. Why not the daughter of Jacob? But just because she “went out” she is called Leah’s daughter, since she, too, was fond “of going out” (Genesis Rabbah 80:1), as it is said (30:16) “and Leah went out to meet him”. With an allusion to her they formulated the proverb: “Like mother, like daughter”.