PLAINS, Ga. — The Sunday school lesson was familiar: When your burden grows heavy, ask God for strength. But the message carried a more powerful and personal meaning than usual because of who delivered it: Jimmy Carter.

The 90-year-old former president taught Sunday school in his hometown for the first time since he disclosed on Thursday that his cancer had spread to his brain.

With easygoing humor and his usual toothy smile, Carter gave two back-to-back Bible lessons to unusually large crowds totaling more than 700 people – some of whom had traveled hundreds of miles – just three days after undergoing radiation treatment.

He spent less than five minutes recapping his illness before saying, “That’s enough of that subject” and beginning the lesson on faith, love and relationships.

Carter said he and his wife of 69 years, Rosalynn, resolved never go to sleep without settling their differences.

“Just being able to admit you MIGHT be mistaken and that the other person MIGHT be right” will improve a relationship, he said, prompting laughter from the crowd at Maranatha Baptist Church.

The turnout was so big that Carter gave a second lesson at the nearby high school for about 250 people, with 70 others turned away. Carter entered and exited both venues without fanfare, wearing a gray suit.