Simply believing in someone named Jesus will not solve the issue for Mormons because — as the apostle Paul warns in 2 Corinthians 11:4 — there are some who preach a different Jesus. For example, while the Bible teaches that Jesus has always existed as God (John 1:1), Mormons see Jesus as someone who worked His way up to godhood. In fact, to Mormons, Jesus is merely one in purpose with God the Father; whereas the Bible declares that the Father and the Son are also one in essence (cf. Phil. 2:6) — that they are both equally God and members of the Holy Trinity.
http://www.equip.org/perspectives/wh...-of-the-bible/