Mattis is a Catholic, and has been described as "devout" and "committed." During the 2003 Iraq invasion, he often prayed with general John F. Kelly on Sundays. The Trump transition team's formal biography of Mattis described him as "the living embodiment of the Marine Corps motto, "Semper Fidelis"." He has declined when asked by reporters to discuss his faith in public. In a 2003 PBS interview, Mattis recalled how his Marines followed advice from his chaplain on gaining the support of Iraqi citizens: