[1] The ASBC was officially formed in 1928 but its origins lie some years earlier when the division between the Arizona Baptist Convention and the Northern Baptist Convention — particularly in respect to segregation and other racial issues — created the same unbridgeable divide that slavery had caused between the ASBC and the NBC in the mid 19th century.

By March 1917, a group of Baptists who objected to the northern positions on segregation and the intermingling of racial groups decided to leave the First Baptist Church of Phoenix and form the Calvary Baptist Church of Phoenix.

On March 27, 1921, with Rock as their pastor, a group of people left the Calvary Baptist Church to form the First Southern Baptist Church, as a protest against the Northern Convention's stances on open communion, alien immersion, and interdenominational comity.

In August of the same year, this new church joined the Southwestern Baptist Association of New Mexico.

[2][3] On September 21, 1928, Rock led the formation of the Baptist General Convention of Arizona.