Why would people be motivated to join such a community? People are motivated by autonomy, mastery and purpose. The purpose of the community (as per 58) is to be prepared and to create, educate and research for the betterment of mankind. If we were to use one single phrase it should be something like:

such a purpose should provide a strong motive for long term members, for the more immediate desires there is the motivation of, health of mind and body, savings, qualifications and practical growth. Finally, there is the motivation to be part of something where you are not only improving yourself but providing a service to humanity.