Schaefer had previously testified that he performed his son's 2007 wedding out of love, not a desire to flout church teaching on homosexuality.
But Tuesday's testimony made clear he has had a change of heart.
“I have to minister to those who hurt and that's what I'm doing,” said Schaefer.
The prosecutor, the Rev. Christopher Fisher, invited Schaefer to “repent of your actions” and pledge never again to perform a homosexual union.
“I cannot,” Schaefer replied.
His son, Tim Schaefer, told jurors he knew he was putting his father in a difficult position by asking him to officiate his wedding. But he concluded he would hurt his father's feelings if he didn't ask.
Schaefer said he hoped his father's trial would start a larger conversation in the denomination.
