The Baal HaTurim says that Har Sinai was detached from its place, and became: כְ הַּ ר עַּ ל גַּ בֵ י הַּ ר like a mountain on top of a mountain. Similarly, Ahron HaCohen was Niftar on: הֹר ה ה ר Hor HaHar, a mountain upon a mountain. Chazal say that Tzaddikim are compared to mountains, and a person who Fargins another person, like Ahron who was a: לֵב שֶּׁש מַּח בִגְדוּלַּת א חִיו heart that rejoiced with his brother’s greatness, is Zoche to have all the Zechusim of the other person, since he is happy with his friend’s successes.
This is why Ahron was buried on: הֹר ה ה ר Hor HaHar, to show that such a person is heading for double Schar in Olam HaBah. (I once told this to R' Schlesinger Shlita and he liked it). We can suggest that’s why Har Sinai became a double mountain, as a Remez to us that we should be M'kabel the Torah and we should keep it the same way Ahron kept it; i.e., with an Ayin Tova and a Simcha with our friend’s Hatzlacha. We should all become like a הֹר ה ה ר Hor HaHar, and share each other’s Avodas Hashem.
Like it says: וַּיִחַּן שׁ ם יִשְר אֵל נֶּגֶּד ה ה ר יתרו יט ב Klal Yisroel encamped before the mountain, and Rashi says that: וַּיִחַּן is a singular Lashon of Achdus (as if the Passuk is speaking about one person) since we were: כֱּאִ ישׁ אֶּ ח ד בְ לֵ ב אֶּ ח ד like one person. This is the true way to be M'kabel the Torah; i.e., when we all work together and Fargin each other, and love each other without jealousy and Sin’as Chinam. The Derech of Ahron should not be an isolated Ma'ala, rather a goal that all of us should strive for, and at least make believe that we are happy with our competitor’s gain. Then we come out ahead and get double Schar.
