It is a requirement of this Deen of Islam that Muslims stick together. And they work together.
Here is a Hadith Sharif:
Yadullahi Ma'al Jamaa'ah!
One simple paraphrase:
"Allah's hand is with the group."
At one level, Islam is all about Jamaa'ah: The Group.
Even though it is all about the individual: Fard.
And the bottomline, as they say, about Jamaa'ah is the magic number 3: three people.
That is the minimum needed to establish Jum'ah.
And that is when -- when there are three individuals together -- "they," according to Hadith Sharif, those three individuals, must elect one of "them" as leader.
What explanation or elaboration does any of this need?