Why do Christians believe it is important that they don't give up meeting together?

Ask the children to imagine what it must be like for athletes training and training and training. Perhaps they sometimes feel tempted to do something else, maybe they think about stopping...  but they don't give up. They keep on training day after day, week after week. 

 
open-sunday-sign-1698635_1920.jpg
 

The Bible teaches that God wants Christians to keep meeting together and to not give up:  ‘Don't give up meeting together’ says the writer to the Hebrews.

The writer knew that it would not be easy. In fact there were some people who had already stopped. ‘Keep going’, urges the Bible writer, ‘even if it’s not easy it’s important that you keep getting together.’