The Torah discusses Rebecca’s pregnancy and the birth of the twins, Esau and Jacob. The Sages elaborate on the differences between the two in terms of their actions.

“The children were agitated within her” (Genesis 25:22). They ran within her: Rebecca would pass near a house of idol worship, and Esau would twitch to emerge…She would pass near synagogues and study halls, and Jacob would twitch to emerge. In that regard it is stated: “Before I formed you in the womb, I knew you…” (Jeremiah 1:5). “The lads grew” (Genesis 25:27). Rabbi Pinhas said in the name of Rabbi Levi: The development of Jacob and Esau is comparable to the growth of a myrtle bush and a thorn bush [which are similar in appearance in their early states of growth] that grew adjoining each other. When they grew, they blossomed, this one with its fragrance and that one with its thistles, and the difference between them was apparent. Similarly, all thirteen years the two of them would go to and come from school and engage in similar conduct. After thirteen years, this one would go to study halls and that one would go to houses of idol worship. (Bereshit Rabba [Theodor-Albeck] 63)