The Previous Rebbe related that when the Rebbe Rashab’s was 4 or 5, his mother, Rebbetzin Rivka, took him to receive a blessing from his grandfather the Tzemach Tzedek. It was on Shabbos of the Torah portion Vayeira, in honor of his birthday which falls on the 20th of Cheshvan.
Upon entering his holy grandfather’s study, the boy burst into tears. When asked why he was crying, young Sholom Ber answered, “Hashem appeared to our forefather Avraham, why doesn’t He appear to me?”
There are two versions of the Tzemach Tzedek’s answer. The first is that “When a Jew of 99 years resolves to give himself a bris, he deserves that Hashem should reveal Himself.”
In the second version, the Tzemach Tzedek answered, “When a ‘tzadik’ of 99 years resolves to circumcise himself, he deserves that Hashem should reveal Himself.”
Our Rebbe adds that even a Jew who served Hashem completely for 99 years like Avraham Avinu, i.e., one “whose days were complete” must circumcise himself. He must remove the worldly covering which hides G-d’s omnipresence.
By comparison, a person who is 100 is compared to someone who has left the world. At that level, the world no longer hides the G-dly light and life within the creation.
It’s not that Avraham Avinu wanted to add something to his earlier service, or that he realized that the mitzvah of circumcision was missing. Rather, Avraham’s whole avodah was to prepare his children to receive the Torah, and the mitzvah of circumcision served as the foundation of that service. In essence, Avraham Avinu’s whole previous service had been incomplete and to perfect it, he needed to be circumcised.
The lesson is that however great our achievements have been until now; we have not reached the level of a “son of 100 years.” Therefore, not only is our current level incomplete, but we also must perfect all our earlier service by removing the covering which obscures the truth of existence-- the G-dly light and life force.