In this week’s Parsha the Torah says קחצי תא דילוה םהרבא םהרבא תודלות הלאו, “These are the children of Avraham, Avraham gave birth to Yitzchak.” On this Pasuk, Rashi asks why does the Pasuk repeats קחצי תא דילוה םהרבא, wouldn’t it be enough just to say םהרבא תודלות הלאו? Rashi says that after Hashem changed םהרבא’s name, Yitzchak was born to emphasizes םהרבא’s new name. A second explanation of Rashi is that people were saying that ךלמיבא was the biological father of קחצי, because when הרש was living with םהרבא she was not pregnant. However, when she was with ךלמיבא for one night, the next Pasuk says that הרש was pregnant. In order to prevent people from saying this, Hashem made קחצי look exactly like םהרבא and the Pasuk says קחצי תא דילוה.
Two questions can be asked on this statement of Rashi. First of all, why are the Rabbis worried about the people who spread false rumors? Also, if םהרבא had children before קחצי, and הרש was the one who could not have children, then why does the Pasuk focus on םהרבא and not הרש?
Rav Yosef Dov Soloveichik explains that a parent has a responsibility of raising a child, and to pass down the parent’s values to the child. This is what םהרבא was trying to do. םהרבא was trying to start the spread of monotheism in place of polytheism. He was trying to pass down this idea to his son קחצי. However, some people said that this task was impossible. Therefore they said that ךלמיבא fathered קחצי, meaning that םהרבא would not be able to fulfill his task and the ideas that ךלמיבא believed in, polytheism, would stay with קחצי. So, the Torah emphasized קחצי תא דילוה םהרבא, that םהברא shaped the personality of קחצי, and that םהרבא’s ideas were passed down to קחצי. Therefore Hashem made them look the same and share the same ideas.