http://revach.net/article.php?id=4532

Section: Moadim   Category: Pesach Sheini
Pesach Sheini: Rav Gedalia Schorr - Accidents Are Not By Accident!
In the second year in the Midbar, people came to Moshe Rabbeinu to complain that they were Tamei (Bahalosecha 9:7), "V'Lama Nigara", why should we lose out on bringing the Korban Pesach because of our Tumah?  Moshe Rabbeinu asked Hashem, who taught him about Pesach Sheini.  Rashi says that really Moshe should have known this before, but Hashem withheld this halacha since "Migalgilin Zchus Al Yidei Zakkai".  These timei'im were zocheh that this halacha should come about through them.

Why did they have a right to complain?  If they were Onsim (either they were Mishael and Elitzafan who were told to carry out Nadav and Avihu or they were the people who carried Yosef's Aron), they were Patur.  Moreover they were Osek in another Mitzva and therefore patur from Pesach.

Rav Gedalia Schorr (Ohr Gedaliyahu) answers with story from the Zohar.  Tanaim were coming back from performing the great mitzva of Pidyon Shevu'im when they met a child who said to them that he can see on their faces that they did not say Krias Shema.  They explained that they were Patur since they were Oseik B'Mitzva.  Despite this valid reason not to say Krias Shema, points out Rav Schorr, their aura was noticeably diminished.  Why?  Because if Hashem wanted, He could have given them a way to do the mitzva without missing Krias Shema.  It was because of something they did wrong that Hashem caused them to miss the mitzva.  It was this something that the child noticed in their diminished aura.

The Temei'im complained to Moshe that they did absolutely nothing wrong, so how could Hashem punish them by making them miss the Korban Pesach because of a different Mitzva that they did?  To this Rashi explains that they were right and they were indeed Tzaddikim Gemurim.  The reason why Hashem caused them to miss Pesach was a reward for their Tzidkus.  He rewarded them by causing the mitzva of Korban Pesach to be told through them.  Migalgilin Zchus Al Yidei Zakkai!

The lesson for Pesach Sheini is that good excuses may excuse you, but if you were more deserving you wouldn't need an excuse.  Hashem is a master orchestrator and can make things perfect, if you are perfect.