In "Young Goodman Brown," who is at the gathering in the woods and what are they doing?

After
witnessing Goody Cloyse consort with the Devil, Brown is left alone and he sees the minister and
Deacon Gookin approaching on horses. He then sees his wife, Faith. He would see both of these
women, the minister, and the Deacon at the gathering in the forest. At the gathering, Brown sees
people from the town's council board as well as people he'd seen in church every Sunday. He sees
a number of other people, even the most "grave, reputable, and pious people" of the
village. In addition to the pious people, Brown sees disreputable people. There at the gathering
was a combination of the good and the wicked:

It was
strange to see that the good shrank not from the wicked, nor were the sinners abashed by the
saints.

The gathering formed to participate in some sort
of Black Mass or Devil worship. One of the purposes of the gathering was also to convert Faith
and Brown:

And there they stood, the only pair, as it
seemed, who were yet hesitating on the verge of wickedness in this dark world.

Herein did the shape of evil dip his hand and prepare to lay the mark of baptism upon
their foreheads, that they might be partakers of the mystery of sin, more conscious of the
secret guilt of others, both in deed and thought, than they could now be of their own.

This was not just a test of Brown's will to resist evil. It gave
him a chance to see that all people are capable of both good and evil. This is something Brown
would not be able to accept.