Good theology is sound doctrine (teaching) about the truths of God, man, sin, and salvation. It has almost always been forged in the heat of controversy, usually in the form of movements and teachings which challenge orthodoxy (sound teaching). So, in response, distinctions must be made, and errors called out. Below are a few excerpts from G. K. Chesterton's discussion about the early church and why it had an interest in dogma and heresy. .. "Now that purity was preserved by dogmatic definitions and exclusions. It could not possibly have been preserved by anything else. If the Church had not renounced the Manicheans it might have become merely Manichean. If it had not renounced the Gnostics it might have become Gnostic." "The creed declared that man was sinful, but it did not declare that life was evil, and it proved it by damning those who did. The condemnation of the early heretics is...