In 1841, Parker laid bare his radical theological position in a sermon titled A Discourse on the Transient and Permanent in Christianity, in which he espoused his belief that the traditions of historic Christianity did not reflect the truth.
In so doing, he made an open break with orthodox theology.
He instead argued for a type of Christian belief and worship in which the essence of Jesus's teachings remained permanent but the words, traditions, and other forms of their conveyance did not.
He stressed the immediacy of God and saw the Church as a communion, looking upon Christ as the supreme expression of God.
Ultimately, he rejected all miracles and revelation and saw the Bible as full of contradictions and mistakes.
He retained his faith in God but suggested that people experience God intuitively and personally, and that they should center their religious beliefs on individual experience.

Parker's West Roxbury church remained loyal.
Sermons and media attacked him, however, when he denied Biblical miracles and the literal authority of the Bible and Jesus.
Many questioned his Christianity.
Nearly all the pulpits in the Boston area were closed to him, and he lost friends.
Parker reacted with grief and defiance.
He remained unwilling to concede that his views placed him beyond the outer bounds of Unitarian liberalism.
After this unwilling break with the Unitarian establishment, he spent two years (1841–1843) adjusting to the reality of his newly controversial and independent career and increasing his social activism on religious grounds.
He began to see himself as a prophetic religious reformer.

Parker accepted an invitation from supporters to preach in Boston in January 1845.
He preached his first sermon there in February.
 His supporters organized the 28th Congregational Society of Boston in December and installed Parker as minister in January 1846.
His congregation, which included Louisa May Alcott, William Lloyd Garrison, Julia Ward Howe, and Elizabeth Cady Stanton, grew to 7000.
In 1841, Parker laid bare his radical theological position in a sermon titled A Discourse on the Transient and Permanent in Christianity, in which he espoused his belief that the traditions of historic Christianity did not reflect the truth. In so doing, he made an open break with orthodox theology. He instead argued for a type of Christian belief and worship in which the essence of Jesus's teachings remained permanent but the words, traditions, and other forms of their conveyance did not. He stressed the immediacy of God and saw the Church as a communion, looking upon Christ as the supreme expression of God. Ultimately, he rejected all miracles and revelation and saw the Bible as full of contradictions and mistakes. He retained his faith in God but suggested that people experience God intuitively and personally, and that they should center their religious beliefs on individual experience.
Parker's West Roxbury church remained loyal. Sermons and media attacked him, however, when he denied Biblical miracles and the literal authority of the Bible and Jesus. Many questioned his Christianity. Nearly all the pulpits in the Boston area were closed to him, and he lost friends. Parker reacted with grief and defiance. He remained unwilling to concede that his views placed him beyond the outer bounds of Unitarian liberalism. After this unwilling break with the Unitarian establishment, he spent two years (1841–1843) adjusting to the reality of his newly controversial and independent career and increasing his social activism on religious grounds. He began to see himself as a prophetic religious reformer.
Parker accepted an invitation from supporters to preach in Boston in January 1845. He preached his first sermon there in February.  His supporters organized the 28th Congregational Society of Boston in December and installed Parker as minister in January 1846. His congregation, which included Louisa May Alcott, William Lloyd Garrison, Julia Ward Howe, and Elizabeth Cady Stanton, grew to 7000.
Theodore Parker