The source is in Parshat Emor. The Torah tells us ‘Venikdashti betoch bnei yisrael’ – these are the words of Hashem – ‘I will be sanctified in the midst of the children of Israel’.
Here we are being told about a community of people worshipping Hashem, but how do we understand the phrase: ‘in the midst of’?
So, we know that in the Parsha of Korach, the Torah tells us ‘Hibbadelu mittoch ha’edah’ – separate yourselves from the midst of this community.
So, there we have the same phrase, ‘in the midst’, with reference to a community and that term ‘edah’ for community is used in Parshat Shelach Lecha, where the ten evil spies are referred to as ‘ha’edah hara’ah hazzot’ – that evil assembly.
So that is how we know that the reference in Parshat Emor to a group of people, in the midst of whom we sanctify the name of God, is ten people.
I find it absolutely extraordinary that we learn about a minyan from two historic events.
One is the Korach rebellion, and the other is the story of the spies.
In both instances we had people within our nation who seriously let us down, but the message of the minyan is that everybody should be included. It is not for us to judge others.
Of course, we need to assess what’s right and wrong, and we do need to make a stand when we believe it is necessary, but having said that, ultimately, we must leave judgment in the hands of God.
When it comes to a community, absolutely everybody should be ‘in our midst’.
Shabbat Shalom.