The pasuk states that if we follow Hashem’s laws, we will be protected by the bris He forged with the Avos. We may ask: If we are obeying the Torah and have our own merits to protect us, why do we need zechus Avos?
The Magid of Dubno zy”a (Sefer Mishlei Yaakov) answers this question with a parable of a man who left his very young son 1,000 gold coins as an inheritance. Before his death, the father asked his friend to raise his son and to keep an eye on his fortune. The friend committed to do this. He brought the boy into his home and raised him like his own child. When he got older, he took him into his business and paid him a salary every month. This went on for several years.
One day, the boy found out that his father had left him 100 gold coins. He thought to himself: Why do I have to work for someone else? Why can’t I live off my own fortune?
He told his guardian, “Give me my money and I’ll take care of myself from now on!”
The father’s friend told him, “Here is your money. Take it and go if you want. But my advice to you would be to put the money away for safekeeping and not to use any of it. If you do start using it, you will waste it little by little until you are left with nothing. It would be in your best interest to continue working for me and making a salary, and to save your money for when you really need it.”
The nimshol is: The Avos entrusted their zechusim to Hashem for safekeeping. They put it all “in the bank”, so that it would be there for their ancestors to use when needed. Hashem does not give it to us all at once, as we would fritter it away and be left with nothing. Instead, He tells us to work on our own and to obey His Torah so that we earn our own “salary” and we are able to retain the zechus Avos in full for future generations.
Accordingly, the pasuk is saying that if we keep the Torah, Hashem will “guard the bris of the Avos”, and keep their zechusim safe for the future.
