Genesis 46:1

Israel came to Beer-sheba Which place he chose in remembrance of the communion which his father and grandfather had had with God in that place. And offered sacrifices That is, extraordinary sacrifices, besides those he was wont to offer at stated times; and this he did, as well to express his gratitude for the preservation of Joseph's life, and the many other blessings which he had received, as by way of supplication to God for his direction in this important affair, whether he might leave the promised land of Canaan, and remove into the idolatrous country of Egypt; and if so, for the divine protection and blessing to be vouchsafed toward himself and family, both in his journey and in Egypt.

Unto the God of his father Isaac Whom Isaac had honoured and served, and who had constantly provided for and confirmed his covenant with him. He mentions Isaac rather than Abraham, to show that though Isaac was much inferior to Abraham in gifts and grace, yet God was no less Isaac's than Abraham's God, and therefore would be his God also, notwithstanding his unworthiness.