Also see Reason 8
The Bible has very clear warnings of another Jesus, another Gospel, another Spirit, and False Apostles.
"If there arises among you a prophet or a dreamer of dreams, and he gives you a sign or a wonder, and the sign or the wonder comes to pass, of which he spoke to you, saying, 'Let us go after other gods'-which you have not known-'and let us serve them,' you shall not listen to the words of that prophet or that dreamer of dreams, for the LORD your God is testing you to know whether you love the LORD your God with all your heart and with all your soul. You shall walk after the LORD your God and fear Him, and keep His commandments and obey His voice; you shall serve Him and hold fast to Him. But that prophet or that dreamer of dreams shall be put to death, because he has spoken in order to turn you away from the LORD your God, who brought you out of the land of Egypt and redeemed you from the house of bondage, to entice you from the way in which the LORD your God commanded you to walk. So you shall put away the evil from your midst.
And the LORD said to me, "The prophets prophesy lies in My name. I have not sent them, commanded them, nor spoken to them; they prophesy to you a false vision, divination, a worthless thing, and the deceit of their heart. Therefore thus says the LORD concerning the prophets who prophesy in My name, whom I did not send, and who say, 'Sword and famine shall not be in this land'-'By sword and famine those prophets shall be consumed!
Your prophets have seen for you False and deceptive visions; They have not uncovered your iniquity, To bring back your captives, But have envisioned for you false prophecies and delusions.
Her prophets plastered them with untempered mortar, seeing false visions, and divining lies for them, saying, 'Thus says the Lord GOD,' when the LORD had not spoken.
"Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravenous wolves.
Then many false prophets will rise up and deceive many.
Matthew 24:24 and Mark 13:22
For false christs and false prophets will rise and show great signs and wonders to deceive, if possible, even the elect.
2 Corinthians 11:3
But I fear, lest somehow, as the serpent deceived Eve by his craftiness, so your minds may be corrupted from the simplicity that is in Christ.
2 Peter 2:1-2
But there were also false prophets among the people, even as there will be false teachers among you, who will secretly bring in destructive heresies, even denying the Lord who bought them, and bring on themselves swift destruction. And many will follow their destructive ways,...
1 John 4:1
Beloved, do not believe every spirit, but test the spirits, whether they are of God; because many false prophets have gone out into the world.
HOW DO WE TEST A PROPHET?, by Sandra Tanner (Great-great-granddaughter of Brigham Young), Utah Lighthouse Ministry
I have included only parts of the article. To see the entire document, please see this link
...The Mormon missionaries...challenged them to pray about Joseph Smith's message and the Book of Mormon...Is this the proper way to determine if his message is truly from God? The Bible never says to test a prophet by prayer, but by his message. Deuteronomy 13 warns that a prophet must teach correctly about God...Paul tells us in Galatians 1:8-9 that even angels can appear with a wrong message. ...In Acts 17:10-12,..."these were more noble than those in Thessalonica, in that they received the word with all readiness of mind, and searched the scriptures daily, whether those things were so. Therefore many of them believed..." ...Paul did not tell them to go home and pray about it. They were praised for searching the scriptures, in other words, testing the message to see if it agreed with the prophecies of the Messiah.
...John made an appeal to fact, not feeling, ...(1 John 1:1-3)...
Peter wrote specifically to warn about false teachers: (2 Peter 1:15-16) "Moreover I will endeavour that ye may be able after my decease to have these things always in remembrance. For we have not followed cunningly devised fables, when we made known unto you the power and coming of our Lord Jesus Christ, but were eyewitnesses of his majesty..." ...in Chapter 3...he refers them to past teachings and facts, not to feelings or prayer.
The Mormons misuse James 1:5. That verse is for wisdom during times of temptation and persecution, not for knowledge or testing a prophet. He goes on to warn in Chapter 4, verse 3, about those who pray (and we assume it was in Jesus name) for the wrong things-"Ye ask, and receive not, because ye ask amiss..." This verse shows our own desires or misdirected ideas can play a part in the answer. If someone claimed God said we should rob a bank and give the money to the poor, would we need to pray about it? God has already spoken on the issue in the Ten Commandments. So why should we pray to know if God and Jesus appeared to Joseph Smith to show him that they are two totally separated gods with resurrected bodies? Or that there were gods BEFORE our heavenly father. (See Smith's sermons in the LDS History of the Church, vol. 6, pp. 305-312, 474-476) Compare his sermons with Isa. 43:10-11, 44:6-8, 24-25, 45:5-6, 18-24, 46:5-10. Joseph Smith contradicts Isaiah-which one should we believe? Christians test prophets, pastors, and teachers by the Bible. LDS test the Bible by their prophets. They go about testing the message backwards. The Bible was here first, therefore Joseph Smith must be tested by it, not the other way around.
Certainly a decision regarding our eternal life is the most important one we will ever make and deserves careful examination. Anyone meeting with the LDS missionaries should know both sides of the issue. There are plenty of facts from LDS sources to show that Joseph Smith taught false doctrine, lied about polygamy (even to his own wife), changed his revelations, gave false prophecies, etc. He hardly meets the test of a prophet. Truth will stand up to investigation.
Another site showing Joseph Smith as a false prophet
This information is very clearly fact and evidence. I do not need to pray about these facts or the evidence to know if it is true or not. I have tested Joseph Smith by The Bible, and he has clearly failed the Biblical test of a true prophet.
My unanswered question was:
Since The Bible is clear that there will be false prophets, is it possible that Joseph Smith was a false prophet?
I was initially devastated when I received this answer that Joseph Smith could most definitely be a false prophet, yet overjoyed to find the truth that I am much safer without following a potentially false prophet!