Readers and commentators have long been puzzled about the opening words of the parashah: “This is the history of Isaac the son of Abraham – Abraham begat Isaac” (Gen. 25:19).
If Isaac was the son of Abraham, it follows that Abraham begat Isaac. Why do we need to be told what is obvious?
Rashi’s explanation, following, as usual, the more ancient interpreters, is that some of that generation suspected that Abraham was not really the father, so God gave father and son similar facial features to prevent any misunderstanding.
A Chassidic homily quotes the rabbinic view that the history of righteous people is their record of good deeds, which may imply that the good deeds you do must be counted amongst your progeny.
Immortality comes not only through your biological descendants, but also through what you do for the world, for God, for other people.
In a metaphorical sense, your good deeds look like you.