Scout and Jem directly experience racism for the first time. What happens?

Scout and Jem first experience racism while attending the First Purchase Church with Calpurnia. One of the members tells Calpurnia the children don't beling there because they are white..... every other member of the church welcomes them.

Lula stopped, but she said, "You ain't got no business bringin' white chillun here—they got their church, we got our'n. It is our church, ain't it, Miss Cal?"

… When I looked down the pathway again, Lula was gone. In her place was a solid mass of colored people.

One of them stepped from the crowd. It was Zeebo, the garbage collector. "Mister Jem," he said, "we're mighty glad to have you all here. Don't pay no 'tention to Lula, she's contentious because Reverend Sykes threatened to church her. She's a troublemaker from way back, got fancy ideas an' haughty ways—we're mighty glad to have you all."