Question: "What is Christadelphianism, and what do Christadelphians believe?"
Answer: The Christadelphian sect was founded in 1838 by John Thomas, a London-born physician-turned-Bible teacher. Like the founders of the Jehovah’s Witnesses, Mormons and Christian Scientists, Thomas believed he alone had found the truth of real Christianity. One wonders how these men could “study” the Bible and come to the conclusion that God would leave humanity floundering in the darkness of error and apostasy for 1800 years, only to finally reveal Himself to one man. Nevertheless, that is what John Thomas taught.
Christadelphianism teaches the same two lies as literally every cult and false religion: it denies the deity of Jesus Christ and preaches a works-based salvation. Regarding the deity of Christ, Christadelphianism teaches that Jesus was more than a man, but less than God. According to A. Hayward, in Great News for the World, p. 41, Jesus was a created being with “strength of character to right some of the most appalling wrongs of his time.” Christadelphians teach that Jesus had a sinful nature and he, too, needed salvation from sin, that he was not pre-existent and did not come into existence until he was born in Bethlehem. The Bible declares that Jesus was sinless. He “committed no sin” (1 Peter 2:22); “in him is no sin” (1 John 3:5); He “had no sin” (2 Corinthians 5:21); He was “tempted in every way… yet was without sin” (Hebrews 4:15). That Jesus was pre-existent is also evident from such passages as John 1, where He (the Word) was “in the beginning with God” (v. 2) and that all things that were created “were created through him” (v. 3) and that “he became flesh and dwelt among us” (v. 14). Denying that Jesus is the second Person of the Trinity is another universal characteristic of cults.
The second universally taught lie is that of salvation by works. The Christadelphians believe that faith in Christ is the beginning point, but salvation is by no means completed there. While they do claim to teach “salvation by grace,” that claim is buried beneath a landslide of demands for works righteousness. Salvation to the Christadelphians is a process, is not given at the point of faith in Christ, is dependent upon “belief in the covenants,” good works and baptism. Salvation, they believe, is the gift of God, but only bestowed on those whose works merit it. The Bible clearly teaches that “all our righteousness is as filthy rags” (Isaiah 64:6), that works cannot save us, and that no one can keep even the smallest part of the law. “For whoever shall keep the whole Law and yet offend in one point, he is guilty of all” (James 2:10). But “Christ redeemed us from the curse of the Law, being made a curse for us…” (Galatians 3:10). The Law, works, and personal righteousness are powerless to save us. Only faith in Christ and His perfect sacrifice on the cross can save us (Galatians 2:16; Romans 3:28; John 3:16). We are saved by faith alone, in Christ alone. “For He has made Him who knew no sin, to be sin for us, that we might become the righteousness of God in Him” (2 Corinthians 5:21). If, as the Christadelphians teach, we must merit our salvation through our own efforts, then Christ died in vain (Galatians 2:21), and the free gift described in Ephesians 2:8-9 is not free at all.
Other unbiblical beliefs of the Christadelphians include the Holy Spirit is an impersonal force; man does not have an immortal soul; Satan is not a personal being, but merely a synonym for any adversary; death is unconsciousness or annihilation; and heaven and hell are myths. Rather than restoring true Christianity, the Christadelphians deny the basic doctrines clearly outlined in the Bible and, as such, are like all false religions – a lie from the father of lies, Satan, who “walks about like a roaring lion, seeking whom he may devour” (1 Peter 5:8).