Rav Dessler zt”l (Michtav M’Eliyahu, volume 1, page 8) asks, why should such a defense be acceptable to Hashem? If two people commit the same crime and come before the judge and the judge “lets one of them off the hook” because he knows his grandfather, and “throws the book at the other one,” is that fair? Yet isn’t this exactly what we are demanding of Hashem—forgive us because of who our grandparents were? Hashem’s judgement is complete truth. Can showing favoritism possibly be truth?

What is the correct interpretation of Z’chus Avos? It is obviously not “forgive my sins because of the good deeds of my parents.”

It is quite different!

Rav Dessler explains that the concept of Z’chus Avos should be understood according to Rabbeinu Chaim of Volozhin’s interpretation of the pasuk “The just man walks in his integrity, happy are his children after him.” (Mishlei 20:7)

Rabbeinu Chaim of Volozhin explains (Ruach Chaim on Avos, Chapter 5, Mishnah 3) that any character trait a righteous person worked on and developed with all of his strength becomes second nature to his children.

In 1825, Czar Nikolai decreed that Jewish children were to be rounded up and shipped off to serve twenty-five years in the army. This was merely a new twist to the venerable tradition of trying to assimilate the Jews. Jewish children were kidnapped by the thousands and shipped across the continent. When they reached their destination, Christian clergymen were waiting for them, happy at the prospect of having so many Jewish souls to save. These children were known as kantonisten—recruits.

No one will ever know how many thousands of such children were kidnapped, never to see their families again, but the following incident is known and recorded: In 1825, over 1,000 Jewish children were lined up along the banks of the Volga River, to be converted en masse. The ceremony began, and when the priests reached the appropriate part of the liturgy, the army officers instructed the children to wade into the water to be baptized.

The oldest children were thirteen years old. As they marched into the river, some of the older boys declared that they would rather drown themselves than be converted to Christianity, and exhorted the younger children to do the same.
These thousand children kept on going deeper and deeper into the river. The Czar’s officers shouted orders to return to the shore, but the children continued to wade forward. Many were chanting “Shema Yisrael”—Hear O Israel, the L-rd our G-d, the L-rd is One!

The army officers cursed at the children’s obstinacy and the priests screamed about ingratitude and everlasting damnation, but the children—every one of them—ended their young lives in the depths of the Volga. (Go, My Son, page 95).
Rabbeinu Chaim of Volozhin asks, how it is possible that so many simple Jews in every generation have willingly sacrificed their lives for the sake of Hashem? The answer lies with the fact that our father, Avraham Avinu, sacrificed his life for the sake of Hashem. Avraham walked into the fiery furnace in Ur Kasdim out of faith in Hashem. Avraham’s children, consequently, have the innate ability to do the same. Kiddush Hashem is natural to us.

Rabbeinu Chaim wrote that the same holds true for all the ten tests Avraham Avinu passed. How is it that Jews in every generation suddenly get the urge to pick up and move to Eretz Yisrael? How did Jews leave behind their material wealth and comforts and go to an unknown land filled with poverty and disease? How can Jews leave their friends and families and settle in a land surrounded by terrorists? Because Avraham Avinu did it. “Now Hashem said to Avraham, go out of your country, from your kindred, and from your father’s house, to the land that I will show you.” (Bereshit 12:1) Our father Avraham paved the way for his children to come to Eretz Yisrael. It became our nature.