"'What are you willing to give me if I deliver him over to you?' So they counted out for him thirty pieces of silver." — Matthew 26:15
Judas Iscariot betrayed Jesus. The gospel accounts are clear about what led Judas to take this step: it was all about the money.
There had been other minor betrayals before this major one. In the circle of the twelve closest followers of Jesus, Judas had been appointed treasurer. As donations came in, Judas was expected to use the money for the group's expenses or to help people in poverty (see John 13:29). But Judas also took some of the money for himself.
Now Judas saw a better financial opportunity—a more lucrative way to take advantage of his relationship with Jesus. Judas investigated, and he learned he could collect thirty silver coins as a reward for turning Jesus over to the people who wanted him dead.
So Judas sold Jesus, his master and teacher.
But earlier Judas had been present when Jesus asked his followers this vital question: "What good will it be for someone to gain the whole world, yet forfeit their soul?" (Matthew 16:26). What had happened?
Apparently Judas no longer valued Jesus as his master, or even as a fellow human being. When Jesus was teaching, Judas heard only the clank of silver coins; when Judas looked at Jesus, he saw only a chance to make some money.