If the organization is recognized as a church, there is no specific percentage requirement for public support and all the money could theoretically come from a single individual. Normally, however, a church has a broad range of contributors and members so that it would meet the public support test if applied. (See Ready Reference Page: "Calculating Public Support.") The IRS would not normally question gifts from one church to another if giving contributions was part of the regular program of the donating church.