Mankind is given the privilege of speaking to Hashem. When engaged in this act we are very particular about the words we use. We do not make up phrases and names. Rather, we adhere to descriptions by Nevi’im and Chazal that have been handed down to us throughout the ages. Hashem is often described as Our God, the God of Avraham, Yitzchak, and Yaakov. This affirms that the God we pray to is the identical one that was so intimately involved with the Patriarchs. We demonstrate a link from the present all the way back to the origin of monotheism with Avraham.
In our Parashah we find Hashem being described in a somewhat limited fashion. After being given evidence of his son's existence, Yaakov decides to go down to Egypt and see his son before he passes away. Perek 46 begins by saying that Yisrael (Yaakov) came to Be’er Sheva where he slaughtered sacrifices to the God of his father Yitzchak. Why does this Pasuk omit any reference to Avraham? Seforno addresses this issue by saying that after Esav sold the birthright to Yaakov, there was a famine. Hashem appeared to Yitzchak and told him not to go down to Egypt and that he will be the recipient of the Promised Land.
Yaakov understood Hashem's desire to keep Yitzchak out of Egypt. Yaakov was now about to go there for personal reasons -to see his son! The acceptance of his sacrifice would show that he was not violating that which his father stood for. Indeed, Hashem tells him in verse three that he should not be afraid of going down to Egypt and that he and his people will eventually flourish.
It is for this reason that Hashem is described as the God of Yitzchak. Yaakov's actions were about to impact directly upon his father's values not those of his grandfather. Rashi, in addressing this issue, quotes Rav Yochanan's opinion in BeReishit Rabbah (94:5) who states that one owes more honor to his father than to his grandfather. What does Rashi have in mind by applying this idea of honor to our Pasuk? Perhaps Rashi has Avraham's mandate in mind, just as Seforno addresses the mandate of Yitzchak.
In Chapter 15 Avraham asks how he will know that he is to inherit the Promised Land. Hashem responds to this seeming lack of faith by saying that he will surely go to a land, be enslaved, and then leave successfully. From Avraham's point of view he was supposed to go to Egypt. However, Yitzchak was not the recipient of the same destiny. When Yaakov was about to go to Egypt, his first duty was to view his action's impact on his father's honor. It would have been a tribute to his grandfather, but since it might have compromised the honor of his father, this issue had to be dealt with exclusively; hence the Pasuk describes Hashem only as the God of Yitzchak!
The common element between these commentaries is that they are focusing on the relationship between parent and child. When we think of Hashem, do we think of an ancient deity who operated most prominently in ancient times? Do we picture Hashem as the Almighty One speaking to Moshe? We certainly do! This notion is indispensable in prayer. However, regarding our actions, we must realize that we are influenced mostly by those closest to us. Our parents, family, friends, and society have great impact upon how we think and what we do. When we act positively as a result of this impact we should recognize it. On the other hand, when we act negatively as a result of this, we should be vigilant in pursuing and identifying the cause. We must realize that Hashem is the God of our parents, family, and friends. Hence, we should surround ourselves with people that show loyalty to Hashem's Divinity so that we can, as Yaakov did, take into account what those around us stand for and never violate their connection and our connection with Hashem.