This week’s sidra gives us an example.
“Isaac sent Jacob away,” we read, “and he went to Paddan-Aram, to Laban ben B’tuel the Aramean, brother of Rebekah the mother of Jacob and Esau” (Gen. 28:5).
Concerning the final phrase, “the mother of Jacob and Esau”, Rashi says, “I do not know what this teaches us”.
His expression of humility puzzles many of the later commentators, though in fact it is missing from many early Rashi manuscripts.
Presuming, however, that his words are authentic, one understands his problem.
The whole story is building up to the point at which Jacob leaves home and goes to live with Laban, and no-one is in any doubt that Rebekah, Laban’s sister, is Jacob and Esau’s mother.
Is Rashi merely fulfilling the rabbinic rule, “Teach your tongue to say, ‘I do not know'”?
Possibly, but other commentators do find an explanation to fit the puzzling words.
They recognise that Esau and Jacob have become enemies, and Esau will willingly kill Jacob for taking the birthright and the blessing. Jacob on the other hand may need to step in first and get to Esau before the latter gets to him.
If both sons stay home, one or both will die. Sending Jacob stops Esau from murdering Jacob, and Jacob from pre-emptively killing Esau.
As the verse says, Rebekah is the mother of both of her sons; she loves them both; and by sending one away she protects the lives of both.
If this is the right explanation, would Rashi be worried that it needed a later scholar to propound it?
It is likely that it would have given Rashi great pleasure and satisfaction.
The fact is that nobody, however great, can know everything and achieve everything, and a new generation has to have the opportunity of achieving its own triumphs.
The important thing is to lay the foundations on which others can build.