Isaac (Yitzchok) resembled his father Abraham in many ways. In fact, he looked so much like his father that there could be no mistake in anybody's mind about their being father and son. Our Sages say that G‑d fashioned Isaac's face to be exactly like his father's because there were some wicked people who spread tales that Isaac's father was Abimelech, king of the Philistines, or that Isaac was a foundling whom Abraham and Sarah adopted. It is impossible, these talebearers said, that Abraham should become a father at the age of 100 years and Sarah at the age of 90. But when people saw Abraham and Isaac with their own eyes, there could be no doubt in their mind that Abraham was Isaac's father, and Isaac was Abraham's son (B.M. 87a).
Isaac was born on the first day of Pesach (Rosh Hashana 11a). He was the first Jew to be born a Jew, whose parents were Jews. He was also the first Jewish boy to be circumcised at the age of eight days.
Isaac was 37 years old, and unmarried, when G‑d commanded Abraham to offer him up as a Burnt Offering. In this connection, our Sages tell us the following story:
Ishmael, who was 13 years older than Isaac, boasted that he was more devoted to G‑d than Isaac. "I was already 13 years old when I was circumcised. I willingly submitted myself to this painful operation. But you, Isaac, were a baby, eight days old. You knew nothing of what was going on . . .
"It does not require so much courage to undergo a Brith," Isaac replied. "A little pain, a few drops of blood, and that's all. But I assure you, if I were commanded this very day to give my whole life to G‑d, I would do it without hesitation!"
No sooner were these words spoken than G‑d commanded Abraham to offer Isaac as a Burnt Offering. This was the greatest test to which Abraham was put during his lifetime, but it was no less of a test for Isaac. Our Sages tell us (what they infer from the text of the Akedah in the Torah) that Isaac knew that he was to be the Offering. For, while all necessary things were taken for the sacrifice, such as firewood, fire, and a knife, the most important thing of all, the lamb, was missing. Isaac knew that his father would not have been so careless as to forget the lamb; there was only one explanation: He, Isaac, was to be the "lamb." His father's reply confirmed this. For, when Isaac asked his father, "Where is the lamb for the Burnt Offering?" Abraham replied, "G‑d will provide for Himself the lamb, for an offering, my son." Abraham hesitated after the word "lamb," as if to say "for an offering-my son." There was no doubt in Isaac's mind any more, yet both father and son were equally determined to carry out G‑d's bidding with all their heart and soul.
After the "Akedah" happily turned out to be only a test of their faith in G‑d and of their obedience to His commands, Abraham immediately sent his son Isaac to Shem, Noah's son, to learn G‑dly wisdom from the man who himself witnessed the Flood and was saved in his father's Ark. Abraham returned home without Isaac, to find that his wife Sarah had passed away, at the age of 127 years. Abraham mourned the death of his wife and buried her in the Cave of Machpelah which he had bought from Ephron the Hittite prince.
At the age of 40 years, Isaac married Rebeckah (Rivka) his second cousin. She was the granddaughter of Nahor, his father's brother. Eliezer, Abraham's trusted servant, had brought her from the City of Nahor (in Mesopotamia), after carrying out most faithfully the mission which Abraham had given him. Rebeckah was a true comfort to Isaac whose heart had been filled with sorrow since the death of his mother. In her piety, kindness and daily conduct in general, Rebeckah was so much like Sarah, that it seemed to Isaac as if his mother was living again.
For twenty years, Isaac and Rebeckah had no children. Then they were blessed with twins, Esau and Jacob. Esau endeared himself to his father by pretending to be very devoted to him and to his ways of piety. Rebeckah, on the other hand, knew that Jacob was by far superior to Esau, and Jacob was her favorite son. Her judgment proved to be right, for when the boys reached the age of fifteen, their different characters became quite obvious. Esau became a hunter and a trapper, a man of the field; while Jacob was the quiet, studious type. In that year, Abraham died at the age of 175 years, and Isaac and Ishmael buried him in the Cave of Machpelah, where Sarah was buried.
While Isaac was mourning for his father, G‑d appeared to him, blessed him and consoled him.
The experiences of Abraham repeated themselves in the life of Isaac in many respects. Thus, there was a great famine in the land, the like of which there had not been since Abraham's time. Isaac went to Abimelech, the king of the Philistines, in Gerar, who had made a peace treaty with Abraham. Like his father, Isaac intended to continue his journey to Egypt, but G‑d told him not to leave the land which had been promised to Abraham and his descendants, and repeated the blessings to him (Isaac). Isaac remained in Gerar, and began to cultivate the soil. G‑d blessed him in an extraordinary way, and he became even wealthier than Abimelech. At the same time, Isaac had brought a blessing to Gerar, and the people prospered for his sake. Yet they were jealous of Isaac's extraordinary wealth. The wells of fresh water which Abraham's servants had dug were now filled by the Philistines with earth, and stopped up. Isaac dug them up again, and there was strife between his shepherds and the local shepherds for the possession of the wells. Isaac was compelled twice to move, and finally he left Gerar and went back to Beer Sheba, where his father had dwelt for many years. Here G‑d appeared to Isaac again, assuring him of Divine protection and blessings.
Soon Abimelech, accompanied by his chief captain and other distinguished friends, came to Isaac and begged him to make a treaty of peace with him. Abimelech readily admitted that he was certain that G‑d was with Isaac and blessed him at every step. Therefore he, Abimelech, had come to apologize for the treatment which Isaac had received in Gerar, and to establish a personal treaty. The treaty was duly concluded.
When Isaac advanced in years, his eyesight became weak. Our Sages give several reasons why it so happened. One reason is that when Isaac lay bound on the altar, the angels in heaven shed tears, and drops fell into Isaac's eyes. It was for Isaac's benefit to be blind at his old age, so as not to see Esau's bad conduct; also not to be able to go out, where people would point at him and say, "There goes Esau's father!"
The story of Isaac's blessings with which he blessed his sons is well known. Having disguised himself in his brother's clothes, Jacob received his father's blessings which were meant for the first-born. Jacob considered that these blessings belonged to him, since he had bought the birthright from his brother. When the real Essau appeared to claim the blessings, Isaac realized that Divine Providence had taken a hand in the matter. Isaac confirmed Jacob's blessings, saying to Esau, "Indeed, blessed he shall be" (Gen. 27:33). Later Isaac sent Jacob to the house of Bethuel to find a wife among the daughters of Laban, Rebeckah's brother. Like his father Abraham at his old age, Isaac was concerned that Jacob should get the right wife, in order to establish the proper home and to transmit the great tradition and legacy of Abraham to worthy children.
Twenty two years later, Jacob returned home. He was the head of a family of twelve sons and one daughter, and the owner of large herds of cattle and sheep, and many servants. Jacob did not find his mother alive; she had died while he was on his way home. Fortunately, his father Isaac was still alive, living in Hebron. Here, in Hebron, Isaac died at the very ripe age of 180 years. Esau and Jacob, now at peace with each other, buried their father in the Cave of Machpelah.