The false prophet comes in sheep’s clothes; his clothes are his words.  His words must be the accepted words of sheep; he learns sheep vocabulary in order to appear one of them.  There is enough truth in his words to not cast suspicion on his false words.  Evil always has to clothe itself with the good, else we would run away from the lie immediately.  The test is their fruit.  In some cases he can be identified by self-service, desire for personal gain, power and influence (Deuteronomy 23:4, Ezekiel 22:27).  The Fruit of the Spirit is not seen in their lives.  There is really not fruit to feed and nourish the soul.  False words can never feed the soul.  Only the truth of Christ and Christlikeness can sustain us.

15 “Beware of false prophets, who come to you in sheep’s clothing but inwardly are ravenous wolves. 16 You will recognize them by their fruits. Are grapes gathered from thorn-bushes, or figs from thistles? 17 So, every healthy tree bears good fruit, but the diseased tree bears bad fruit. 18 A healthy tree cannot bear bad fruit, nor can a diseased tree bear good fruit. 19 Every tree that does not bear good fruit is cut down and thrown into the fire. 20 Thus you will recognize them by their fruits.” Matthew 7:15–20 (ESV)