Authorities are looking for two people who allegedly stole a preacher's wallet and went on a shopping spree while he was giving a sermon about showing mercy to others.

The Rev. Rob Hamby was the guest preacher at Fort Worth Presbyterian Church on Sunday when his briefcase was stolen from the church office. Security cameras caught images of a man and woman.

"What troubles me is that they would go to the church, not for help but to steal. I am shocked and frustrated that these people did it. But more than anything, I feel kind of sorry for them," Hamby said in Monday's online edition of The Dallas Morning News.

The newspaper reported that about $2,000 in purchases were made on his credit and debit cards before he finished preaching, including the purchase of a $676 diamond ring. In addition to his wallet, Hamby's computer valued at $2,600 was taken.

Hamby, who works as a campus minister at Texas Christian University, said he could have understood if the thieves used his credit cards to buy essentials but not luxuries that they did not need.