Many cults “believe in Jesus” in different ways, but are definitely not Christian in the biblical sense. Their doctrine/beliefs would be contrary to biblical teachings. Mormons cannot be considered Christian because they believe in a different gospel, and therefore a different Jesus. According to LDS teaching, the Book of Mormon (“Another Testament of Jesus Christ”) came about after Joseph Smith was visited by an angel named Moroni who said he had a lost record to restore that taught the fullness of the gospel of Jesus Christ. Paul warned in 2 Cor. 11:4 that there will be other gospels presented with a different Jesus. In verse 14 of this same chapter he warns that Satan can appear as an angel of light. In Gal. 1:6-8 Paul says “I am astonished that you are so quickly deserting him who called you in the grace of Christ and are turning to a different gospel— 7 not that there is another one, but there are some who trouble you and want to distort the gospel of Christ. 8 But even if we or an angel from heaven should preach to you a gospel contrary to the one we preached to you, let him be accursed.”
The Book of Mormon teaches a gospel totally contrary to the one taught in the New Testament, e.g., “we are saved by grace after all we can do.” The Jesus of the Book of Mormon does not offer salvation as a free gift, but only after we have worked for it. The Book of Mormon also teaches that the Bible has been corrupted and changed so that the true gospel of Jesus Christ (i.e. the Mormon gospel) has been lost from it. Matt 24:24 tells us that there will be false christs and false prophets in the last days. The Jesus of Mormonism is a false christ. According to Joseph Smith, Jesus and God the Father appeared to him personally and told him that all of the Christian sects were an abomination in their sight and that he was to restore the true church to the earth. This implies that any Bible-based Christian church is contrary to the teachings of Mormonism, hence, a different gospel. In recent years, the Mormon Church has made an effort to appear more mainstream and garner acceptance among mainstream Christianity. Google the media campaign “I am Mormon.” This is part of an effort to convert more people to their religion. They will say, “We believe in Jesus the same as you! And we believe in the Bible!” This is extremely misleading in light of their belief in the fallibility of the Bible and the gospel of Jesus Christ found therein.