A controversial teaching, presumably originating with Irvine, was that of the "Living Witness Doctrine" (first recorded mention in a convention sermon by Joseph Kerr in 1905, which he later recanted after leaving the group). According to this precept, faith and salvation could only come about through hearing the word preached from the lips of, and seeing the gospel lived in the sacrificial lives of, the true ministry (the "Living Witness"). As a consequence of this doctrine, some were expelled over the following years (among whom was Irvine's early companion, John Long). 1906 found Irvine in San Francisco during the great earthquake.