Balak

When Bilaam finally came to Balak to aid him in his quest to curse the Jews, he blessed them, instead. He began by saying כי מראש צרים אראנו ומגבעות אשורנו , for from its origin, I see it rock-like, and from the hills do I view it.

Rashi explains that he was saying, I look at their origin, their roots, seeing them entrenched & strong like the אבות & אמהות. The Midrash says that  צרים, rocks, refer to the אבות while מגבעות , hills, refer to the  אמהות.

The בן איש חי brings our attention to an anomaly that we find by the Patriarchs & Matriarchs of our nation. Avraham, as we know, was unable to have children until Hashem performed a miracle for him. All the  אמהות , as well, were barren until Hashem healed them. Why was that? It can't be that it happened by chance. What was the reason for this inability to naturally have children?

He explains as follows. When a person brings a child into the world, he is also considered to have fathered his grandchildren & great grandchildren throughout the generations. After all, he is the one who empowered his son to have children as well as his son after him. What Hashem wanted to do here was sever the ties that the כלל ישראל would have had with the ancestors of our  אמהות & אבות; that Terach, Lavan, Besual etc should not have any connection to our nation. Therefore, Hashem made them all barren so that their power to conceive came not from their parents, but rather from Hashem Himself.

This, says the בן איש חי, is how we can explain what Hashem said to Bilaam: לא תאור את העם כי ברוך הוא , you shall not invoke curse upon the people, for it is blessed! You have no possibility to curse the children of the אמהות & אבות for they are blessed. If you should think that you can curse them as the children of Terach or Lavan for they aren't blessed, know that because the אמהות & אבות were barren, there are no ties to those people anymore so the curses can't  take effect.

Why was it so important for Hashem to sever all ties to the fathers of our forefathers ?

The end of that posuk says, הן עם לבדד ישכן ובגוים לא יתחשב, behold! It is a nation that will dwell in solitude and not be reckoned among the nations. The Bais Halevi says that Bilaam recognized the destiny of the Jewish nation; that as long as they dwell in solitude & don't mingle with the other nations, they will dwell in peace & no one will be able to have power over them. This is how he reads the posuk: הן עם לבדד , if they will be in solitude, then  ישכן , they will dwell peacefully. However ובגוים, if they will mix with the nations,   לא יתחשב , then Hashem will cause that they won't be reckoned among them, rather they will be scorned by them.

This scorn that the nations have for us which helps keep us apart from them, is exemplified by this story. Once the Besh"t was on his way back from the mikva when he saw a group of gentiles standing around. He thought to himself, I hope none of them touch me rendering me impure. As he walked by, he heard one of them say to his friend, “be careful; don't let that Jew touch you & contaminate you.” When the Besh"t would relate this story, he would explain that this is the meaning of Bilaam's words. We are able to remain a nation that dwells in solitude because the gentile looks down on us

Perhaps this is why Hashem had to sever all ties with our forefathers’ fathers. In order for our nation to truly live alone, we must not have any ties to the outside world. If we were still considered descendants of Terach, etc, then we would still be connected to that world. The only way our nation can survive is by being a nation alone. Hashem had to sever all ties for us to remain unique & alone ensuring the survival of the Jewish people!