The circumstances connected with the birth of her twin sons were as remarkable as those during the period of Rebekah's pregnancy. Esau was the first to see the light, and with him all impurity came from the womb;[22] Jacob was born clean and sweet of body. Esau was brought forth with hair, beard, and teeth, both front and back,[23] and he was blood-red, a sign of his future sanguinary nature.[24] On account of his ruddy appearance he remained uncircumcised. Isaac, his father, feared that it was due to poor circulation of the blood, and he hesitated to perform the circumcision. He decided to wait until Esau should attain his thirteenth year, the age at which Ishmael had received the sign of the covenant. But when Esau grew up, he refused to give heed to his father's wish, and so he was left uncircumcised.[25] The opposite of his brother in this as in all respects, Jacob was born with the sign of the covenant upon his body, a rare distinction.[26] But Esau also bore a mark upon him at birth, the figure of a serpent, the symbol of all that is wicked and hated of God.[27] The names conferred upon the brothers are pregnant with meaning. The older was called Esau, because he was 'Asui, fully developed when he was born, and the name of the younger was given to him by God, to point to some important events in the future of Israel by the numerical value of each letter. The first letter in Ya'akob, Yod, with the value of ten, stands for the decalogue; the second, 'Ayin, equal to seventy, for the seventy elders, the leaders of Israel; the third, Kof, a hundred, for the Temple, a hundred ells in height; and the last, Bet, for the two tables of stone.[28] THE FAVORITE OF ABRAHAM 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.[29] 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.[30] 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.[31] 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.[32]