That ceremony was performed in opposition to the signing of the bill. Some of the protesters said they are Catholics upset over the exorcism rite.
In a news conference, the bishop seemed to call into question the motives of those who support pro-same sex marriage politicians.
"If you're voting for someone because you have the intention of trying to promote something that is gravely sinful then you are putting your salvation in jeopardy," said Bishop Thomas Paprocki, Roman Catholic Diocese of Springfield.
As people were leaving the church, some of the protesters held up pictures of their gay loved ones.