In this week's Parsha, we read of Hashem's appearance to Avraham after his Bris-Milah. Why did Hashem reveal himself to Avraham specifically after the Bris? Apparently, there must have been something about Avraham's performance of this Mitzvah that merited Hashem visiting him.
Rabbi Shalom Ber of Lubavitch (a previous Lubavitcher Rebbe) once went as a young boy to receive a birthday Beracha from his grandfather, the Tzemach Tzedek (the third Lubavitcher Rebbe). All of a sudden, the boy started to cry. When asked what was wrong, he told his grandfather that he had learned that Hashem had revealed Himself to Avraham and he was crying because Hashem does not reveal Himself to any of us. The Tzemach Tzedek replied that because this man of ninety-nine years of age was willing to circumcise himself right away, he was worthy of having Hashem reveal Himself to him. The Tzemach Tzedek was explaining that the greatness of Avraham Avinu was that he acted immediately and promptly to fulfill the words of Hashem. Despite the fact that he was already considered a righteous man who no longer had to prove his belief in Hashem, he acted without hesitation to do what Hashem asked. For this action, he deserved a visit from Hashem. Most people today, however, do not have the level of commitment necessary to be able to obey Hashem without hesitation.
Another version of this story relates that the Tzemach Tzedek replied that this righteous man of ninety-nine years of age decided that he must circumcise himself, and thus was worthy of having Hashem reveal Himself to him. This version implies that the Tzemach Tzedek was stressing the decision made by Avraham Avinu. Despite his desire to obey Hashem, Avraham had to consider in his mind the personal difficulties involved in doing this. He was an old man and this was a painful procedure. Nevertheless, Avraham came to the emotional and intellectual decision that he had to obey Hashem and thus deserved a visit from Hashem. It is very difficult for the average person to be able to make such a decision, especially when faced by pain and discomfort.
According to both versions, we may learn from Avraham Avinu what is necessary to have a strong relationship with Hashem. We must be ready to obey His wishes without hesitation and we must also arrive at the decision to do so despite whatever emotional and intellectual difficulties may come up. Perhaps we too will then witness Hashem revealing Himself to the world.