The comment drew big laughs from the crowd as Paul went on to criticize Obama for referencing the Bible as a part of his support.
"It did kind of bother me, though, that he used the justification for it in a biblical reference," Paul said. "He said the biblical Golden Rule caused him to be for gay marriage. And I'm like, what version of the Bible is he reading? I don't know what version he's getting it from."
Despite the Iowa crowd's support, some conservatives are distancing themselves from Paul's comments. Family Research Council President Tony Perkins told CBS's Bob Schieffer that Paul was wrong to mock the president, saying Obama's views are no "laughing matter."
"I don’t think this is something we should joke about," Perkins said on Sunday. "We’re talking about individuals who feel very strongly one way or the other, and I think we should be civil, respectful, allowing all sides to have the debate — I’m glad that’s what you’re doing here this morning — but I think this is not something to laugh about, to poke fun of other people about."