The pioneers of the Seventh-Day Adventist Church were Arian and semi-Arian in their Christology—many coming from a heretical sect called the Christian Connexion—a restorationist off-shoot. Their position only started to shift after 1888. This is one of the major red flags and evidences that their movement was not started by God. He did not use Christological heretics that resurrected ancient heresy to restore His Church.
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