While Esau and Jacob were little, their characters could not be judged properly. They were like the myrtle and the thorn-bush, which look alike in the early stages of their growth. After they have attained full size, the myrtle is known by its fragrance, and the thorn-bush by its thorns.
In their childhood, both brothers went to school, but when they reached their thirteenth year, and were of age, their ways parted. Jacob continued his studies in the Bet ha Midrash of Shem and Eber, and Esau abandoned himself to idolatry and an immoral life. Both were hunters of men, Esau tried to capture them in order to turn them away from God, and Jacob, to turn them toward God. In spite of his impious deeds, Esau possessed the art of winning his father's love. His hypocritical conduct made Isaac believe that his first-born son was extremely pious. "Father," he would ask Isaac, "what is the tithe on straw and salt?" The question made him appear God-fearing in the eyes of his father, because these two products are the very ones that are exempt from tithing. Isaac failed to notice, too, that his older son gave him forbidden food to eat. What he took for the flesh of young goats was dog's meat.