The Rambam says that the main occupation of the great Sanhedrin that sat in the Bais Hamikdash was to ascertain the Yichus of each Cohen, and also to check each Cohen if he had a Mum (physical blemish). If he was verified kosher, he would put on white clothes, and go be: נִכְנ סַוּמְש מֵשַעִםַאֶח יוַה כֹּהֲנִים join in the Avoda together “with his brothers the Cohanim”.
Actually, the Rambam uses the exact same words as the Mishna in the end of Maseches Middos: נִכְנ סַ וּמְש מֵשַ עִםַ אֶח יוַַה כֹּהֲנִיםַמשנהַסוףַמדות.
Perhaps, the expression: עִםַאֶח יוַה כֹּהֲנִים “with his brothers the Cohanim” has a message. When a Mishmar (designated group) of Cohanim left the Bais Hamikdash after doing Avoda for a week, they would give a Bracha to the incoming Mishmar, that Hashem should give them Achdus. (Gemara). R’ Avigdor Miller Zatzal points out that they don't give them a Bracha about keeping the Halachos of Avoda properly. We see the importance of Achdus and Middos Tovos, more than anything else.
Indeed, there is nothing better and more precious than becoming a Lamdan or a Baal Halacha. But not at the cost of Mussar! Chazal criticize the Cohanim. When a Cohen stabbed his friend to death (they had been vying over the privilege to do an Avoda) all the father of the dying Cohen was concerned about was that the knife should not become Tamei; not the loss of his son's life. (Gemara).
This is an extreme of how Dikduk in Halacha can be totally crooked, Rachmana Litzlan. I was once about to daven Maariv, and a Mashgiach who is a Talmid of R' Shlomo Wolbe Zatzal told me: "Come, let's daven Maariv together." This is the beauty of a Baal Mussar who involves himself in Tikkun HaMiddos.
We Need to Always Feel "It's Us Being Ovdei Hashem Together"
This is the way Cohanim should do Avoda: “It’s us!” Not “each person being a separate entity”. I knew an elderly Jewish couple who felt each other's pain when they were sick (they weren't even frum, but their children became frum). Notice how the Cohanim constantly needed Brachos from each other. מִיַשֶשִכֵןַאֶתַשְמוַֹבּ בּ יִתַה זֶּה,ַהוּאַי שְכִיןַבֵּינֵיכֶםַא הֲב הַ וְא חְו הַ וְש לוֹםַ וְרֵעוּת He who establishes His Name in this house, shall establish between you Ahava, Ach’va (brotherliness), Shalom & Rei’us (friendship).
We can suggest that there was a worse problem of Achdus Davka in the Bais Hamikdash, since being in the house of Hashem they got carried away. Like the person who was bentching, and when he got to the words: וּבְַנֵַיַיְַרוּש ַל ַיִַם “Hashem, please rebuild Yerushalayim!”, he killed himself with a knife! And it's “Halacha L’ma’aseh” – no knives on table during Bircas HaMazon. (Shulchan Aruch).
Yet, all of us need to always feel "It's us being Ovdei Hashem together", and to be happy with each other's accomplishments. And indeed, doing things in a group has much more power and Chashivus.
STORY
I was in Monroe to see R’ Gershon, and we were going towards the main room where everyone was sitting and eating L’chavod the Rebbe’s Yahrzeit. It was a large crowd, and you had to make your way through them, especially R’ Gershon who had a seat on the dais. He invited me to join him, and he stretched out his hand to take mine. He said with a smile: “It’s not easy in this place. Let’s hold hands and go together”.
