The central theme of the Bible is God's plan to bring us back to Himself–and this plan was fulfilled, totally and completely, in Jesus Christ.
In other words, we do not need to look for another Savior, nor do we need to add anything to what Jesus Christ has already done for us. Christ came down from heaven according to God's plan–and by His death and resurrection He did everything that is necessary to make our salvation possible. The Bible says, "For Christ died for sins once for all, the righteous for the unrighteous, to bring you to God" (1 Peter 3:18).
This is why Christians have always rejected attempts to add any later books to the Bible. The Bible's message is complete–and the reason is because Christ's work is complete. Without exception, these later so-called "revelations" deny the Bible's teaching about Jesus' divinity, or say that He cannot save us. But the Bible says otherwise.
Don't be misled by those who claim the Bible's message is incomplete. God's plan for our salvation was finished through Christ's death and resurrection for us. The Bible says, "Salvation is found in no one else, for there is no other name under heaven given to men by which we must be saved" (Acts 4:12). Are you trusting Christ alone for your salvation?