People often make a distinction between being "spiritual" and being "religious," but often can't really distinguish between the two except to say that religion is organized, while spirituality is organic. It could also be said that spirituality is personal and religion is communal.
Although there is some debate over the etymology of the word "religion," one possibility that affirms this view of religion as communal is that it derives from the Latin "religare," which means to tie or bind (it's the root word for ligament, too!).
In that sense, then, religion is what binds us together. It follows that religious education is the process by which we learn about these ligaments, and, as it happens, the process itself fosters the creation of bonds between us.