The rally comes in the wake of an act of vandalism perpetrated against the church nearly two weeks ago.
"What we know is, our voices echo even louder than theirs for justice love," said Rev. Jason Lydon, with Second Unitarian Church.
On was August 24, around 1 p.m., two women were caught on cell phone video throwing rocks at the church and the sign in front of it. Apparently offended by its pro-abortion rights message.
No one was in the building and the damage was limited to broken glass, but those who came out for Sunday's rally see the intent behind it as the real problem.
"I feel so violated because someone attacked our church and did damage to our church over something we believe," said Susan Richards, a member of Second Unitarian Church.
"Acts of violence don't occur in a vacuum," Rabbi Brant Rosen, with Congregation Tzedek Chicago added. "This is part of an overall culture of incitement and violence that is going on in our country."
Second Unitarian Church is known for its progressive stance on a range of social issues, not just abortion. Supporters include members of the church, but also of like-minded religious congregations around the city.
"The bottom line is, we show up. We show up for our friends and neighbors here and because our cause is critical to democracy," said Gail Stern, a supporter of Second Unitarian Church. "My field is sexual violence prevention and those two issues are really connected because it has to do with someone having the autonomy to decide what happens or does not happen to their own body."
While the damage to the sign in front of the church has been fixed, a fist-sized hole remains on the stained glass window. The two women who perpetrated the act of vandalism have not yet been identified.