As naught was holy to Esau, Jacob made him swear, concerning the birthright, by the life of their father, for he knew Esau's love for Isaac, that it was strong.[49] Nor did he fail to have a document made out, duly signed by witnesses, setting forth that Esau had sold him the birthright together with his claim upon a place in the Cave of Machpelah.[50] Though no blame can attach to Jacob for all this, yet he secured the birthright from him by cunning, and therefore the descendants of Jacob had to serve the descendants of Esau.[51] ISAAC WITH THE PHILISTINES The life of Isaac was a faithful reflex of the life of his father. Abraham had to leave his birthplace; so also Isaac. Abraham was exposed to the risk of losing his wife; so also Isaac. The Philistines were envious of Abraham; so also of Isaac. Abraham long remained childless; so also Isaac. Abraham begot one pious son and one wicked son; so also Isaac. And, finally, as in the time of Abraham, so also in the time of Isaac, a famine came upon the land.[52] At first Isaac intended to follow the example of his father and remove to Egypt, but God appeared unto him, and spake: "Thou art a perfect sacrifice, without a blemish, and as a burnt offering is made unfit if it is taken outside of the sanctuary, so thou wouldst be profaned if thou shouldst happen outside of the Holy Land. Remain in the land, and endeavor to cultivate it. In this land dwells the Shekinah, and in days to come I will give unto thy children the realms possessed by mighty rulers, first a part thereof, and the whole in the Messianic time."[53] Isaac obeyed the command of God, and he settled in Gerar. When he noticed that the inhabitants of the place began to have designs upon his wife, he followed the example of Abraham, and pretended she was his sister.[54] The report of Rebekah's beauty reached the king himself, but he was mindful of the great danger to which he had once exposed himself on a similar occasion, and he left Isaac and his wife unmolested.[55] After they had been in Gerar for three months, Abimelech noticed that the manner of Isaac, who lived in the outer court of the royal palace, was that of a husband toward Rebekah.[56] He called him to account, saying, "It might have happened to the king himself to take the woman thou didst call thy sister."[57] Indeed, Isaac lay under the suspicion of having illicit intercourse with Rebekah, for at first the people of the place would not believe that she was his wife. When Isaac persisted in his statement,[58] Abimelech sent his grandees for them, ordered them to be arrayed in royal vestments, and had it proclaimed before them, as they rode through the city: "These two are man and wife. He that toucheth this man or his wife shall surely be put to death."