Another interpretation of "And Dinah went out" (Genesis 34:1): But did she go out because of sin? For Jacob had said, "I am too small for all the kindnesses" (Genesis 32:11 [10]). Rabbi Acha said: The Holy One, blessed be He, said: "I have fed your ancestors from their own deeds, and yet you say, 'I am too small'?" The Holy One, blessed be He, said to him: "Jacob, it is on account of your righteousness that I performed for you all these miracles of which you say, 'I am too small.' But behold, she is going out, and let your merit stand for you." And so, "And Dinah went out."
Why Jacob Called Himself Unworthy Before Dinah Went Out
Midrash Tanchuma Buber, Vayishlach 16:1
ד"א ותצא דינה. ומן חטייא שאמר יעקב קטנתי מכל החסדים (בראשית לב יא), אמר ר' אחא האכלתי את אבותיך ממעשיהם ואתה אומר קטנתי, א"ל הקב"ה יעקב בצדקתך עשיתי לך כל הנסים הללו שאתה אומר קטנתי, אלא הרי היא יוצאה ותעמוד לך זכותך, ותצא דינה.