"Why Should We Be Deprived?"
Why shall we be deprived, so as not to offer the sacrifice of G-d?
Although the proper time for the Passover offering was 14 Nisan, some Jews were forbidden to participate because they were in a state of ritual impurity. Appealing to Moses, they protested their lot, claiming that it was unfair that they be excluded from this mitzva.
G-d acceded to their request.
The mitzva of Pesach Sheni was given, affording those who were unable to offer the Passover sacrifice at the proper time because of ritual impurity or physical distance from Jerusalem a chance to do so one month later.
Because of the sincere entreaty of a small number of Jews, an additional mitzva was included in the Torah.
We are taught that the Final Redemption will also come about in the same manner.
In exile all Jews are ritually impure and distant from G-dliness.
Yet every Jew has the right to demand that G-d allow us to offer the Passover sacrifice at the Third Holy Temple, as well as the power to bring this into actuality.
(Likutei Sichot, Vol. 27)