Occultic sources of prophecy include psychics, tarot cards, Ouija boards, astrology, horoscopes, clairvoyants, mediums, ESP, witchcraft, divination, and so forth. (Isaiah 47:13)

Not everyone that gives you a false prophecy is malicious, they are just confused. Sometimes they are walking in their own delusion, thinking they are hearing God when they are not. (Jeremiah 23:26)

Desires are a natural function of the human emotion. Desires are linked with our wishes, aspirations, urges, and expectations. Gone unchecked, desires can cause us to rebel against the will of God in our lives… Many times we can so yearn to have something that we will listen for any voice that will align with out desires. False prophecy, therefore, can come through a desire so unrestrained that we can no longer discern the voice of the Lord over the voice of the enemy or our own flesh.  

Prophecy has been used to try and manipulate people into actions they may not otherwise take. (Ezequiel 13:17)

There are true prophets that have not yet matured in their gifting that may deliver a word from the Lord mixed with their own emotions. Therefore the word is impure.

The enemy is able to counterfeit prophetic dreams, just as he is able to counterfeit prophetic words. (Jeremiah 23:32)

Just as the Lord can send angels to prophecy, the enemy can also send one of his hosts to deliver a demonic prophecy. (Jeremiah 23:13)