Agile is successful only when the team actually doing the work is empowered, self-organized, and is driving change from within–rather than experiencing it from above.
This team is commonly known as the Team of Peers, or the Core Team.
One of the Core Team's most important responsibilities is to learn as much as it can about Agile and use this knowledge to perfect its process. The team must collaborate and reach consensus on this process, as well as any changes made to it over time. If the Team is successful, its members very likely will find themselves mentoring other project teams in the organization.
- The Role of the Core Development Team in an Agile Project (CIO Magazine)