Bonding through ritual! A sense of community through very explicit shared values. A default norm of helping other people in the community. A group "meditation" on being loving/virtuous. Also you can learn about the Bible and meet children.
Oh also a collective airing of the most important or vulnerable thing to each person, and an agreement to all quietly feel for you what you're feeling and to beg the Lord for your needs to be fulfilled. Prayer requests are dope.