They don't just follow rules, they implement them. They don't just attend the worship service, they perform specific functions to ensure that orderliness being observed in every way. They don't just join in various Church activities, they lead the brethren to actively participate in such spiritual endeavors.
They are the Church officers-deacons and deaconesses, choir members, secretaries, finance officer and so on. We see them in every congregation of the Iglesia ni Cristo any where in the world, sacrificing much time and effort if only to fulfill the duties and obligations entrusted to them.
As taught in the Bible, duty in the Church is a spiritual gift from God (Rome 12:6-8). In the apostolic era, "God chose some people to be apostle and prophets and teachers".