 Soon afterwards, in October 1827, he fell from a horse and was seriously injured.He later stated that it was during this time that he began to believe that the "kingdom" described in the Book of Isaiah and elsewhere in the Old Testament was entirely different from the Christian church.Over the next five years, he developed the principles of his mature theology — most notably his conviction that the very notion of a clergyman was a sin against the Holy Spirit, because it limited the recognition that the Holy Spirit could speak through any member of the Church.