Rep. Elijah Cummings has been in the House for nearly 20 years, but it’s his time as Rep. Darrell Issa’s sparring partner that probably earned him the most media attention.

And for that, his own mom thinks Cummings owes Issa some kindness.

The Maryland Democrat had the crowd at the National Treasury Employee Union’s 2015 Annual Legislative Conference roaring last week when he explained to them why he was nice at Issa’s official portrait unveiling. (Loop fans may remember that’s the Oversight and Government Reform Committee Chairman portrait that his successor, Rep. Jason Chaffetz, promptly took down.)

Cummings, who as Oversight’s ranking Democrat battled Issa on such hot-button topics as Benghazi and the IRS scandal, said the California Republican’s office invited him to the unveiling, but probably didn’t expect him to show.

But he went, and was called on to speak. And he was nice … because his mother told him to be.

“My 88-year-old former sharecropper mother said don’t be mad at that man,” Cummings said. “That man done made you famous.”