PLAINS, Ga. -- On Sunday, President Jimmy Carter shared an update on his cancer battle and his efforts to mediate a dispute between Martin Luther King Jr.'s children.

The humanitarian said it's easier to find common ground on the world stage than this one.

President Carter opened up about the King family heirloom legal dispute while he taught Sunday school at Maranatha Baptist Church in his hometown of Plains, Ga.

"Earlier this summer they asked me if I would try to mediate the dispute," Carter said. "And I'm finding it's more difficult than - than finding peace between Israel and Egypt. But I haven't given up yet."

President Carter also told the crowd he's undergone radiation treatment in four places in his brain and that he'll better know how it's affected him in several weeks.

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