For five decades John Rainbow managed the central finances of the Oxford Group, the Christian charity that campaigned under the name of Moral Re-Armament (MRA, now Initiatives of Change). The aim of the charity, formed in 1938 as the second world war loomed and nations re-armed themselves militarily, was to build "a hate-free, fear-free, greed-free world". John joined the group's board of trustees in 1976 and served on it until 1993. As chief accountant he thought carefully about the individuals who donated money and one of his top priorities was thanking them immediately. He was also keen to keep them informed about news and events. His work was founded on his personal faith.
Accountant, John Rainbow managed MRA finances in Britain.