http://revach.net/article.php?id=4568

Section:  Avodah   Category: Ahavas Yisroel
Parshas Bahaloscha: Rav Yaakov Kaminetzky - A Slap To The Shechina

Hashem tells Moshe after he davens on behalf of his sister Miriam who spoke Lashon Hara about him, that she must be in isolation for at least seven days.  Why?  The pasuk says that if her father was angry with her she would need seven days isolation, so surely when one  provokes Hashem's  anger one should deserve isolation .  Rav Yaakov Kaminetzky asks why the whole drasha?

Rav Yaakov says that this pasuk is teaching us a very important lesson.  After the incident when Miriam was punished with tzoraas, Aharon asks Moshe to forgive her.  Aharon makes no mention of Hashem since he thought that since this was a Chait Bain Adam LaChaveiro all you need for tshuva is your friends forgiveness.  Moshe then asks Hashem to remove her tzoraas. Moshe's tefilla to Hashem is a obvious demonstration of his wholehearted forgiveness of his sister .There would be good reason to assume  that there is no need for her to continue to suffer.

Hashem's response is that her offense was not only perpetrated against Moshe but also against Hashem.  Each person is a Tzelem Elokim, and any infraction towards another person is also a sin against Hashem in whose image the person was created.  This is why Hashem tells Moshe by invoking the anger of the Shechina, that she must still be punished because the aveira was not towards Moshe alone.

Taking this a step further, although Rav Yaakov clearly does not say this, maybe we can say that Bain Adam LaChaveiro is really just another form of an aveira towards Hashem.  When we harm our friends, it is the Tzivui of Hashem that we have violated.  The only difference though between this and Bain Adam LaMakom is that the subject matter of the infraction is a live human being.  This complicates the situation enormously because a human is dynamic and not static.  Any interaction we have, either directly or indirectly, is subject to deep sensitivities that we will be held accountable for.

Maybe the Mishna in Yuma (85b) alludes to this way of thinking when it says that for Aveiros Bain Adam LaChaveiro, Yom Kippur is not Michaper until your friend forgives you.  Clearly the Mishna understood that the real kappara comes from Hashem whose words you have not heeded.  The only catch is that you must first reverse the damage and at least attempt to make amends with your friend  so that ultimately he is no longer  angry with you.  

Based on this way of understanding we can understand why you must only ask your friend forgiveness three times and it also explains how we can obtain forgiveness from those who are no longer alive.  The Mishna then ends with the famous Rebbi Akiva who tells us that only Hashem can cleanse us.  Ashreichem Yisroel!