Simplify the following text for a Grade 4 native English-speaking person.
Original: He arranged a group of up to 5,000 people to sing in a choir and then preached the gospel and invited people to come forward ( a practice begun by Dwight L. Moody ) .
Simplified: Groups of up to 5,000 people would often sing in choir at his meetings . Graham would preach the gospel and then invite people to come forward .