Matt 7:15-23 (ESV)
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 thornbushes, 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.
21 “Not everyone who says to me, ‘Lord, Lord,’ will enter the kingdom of heaven, but the one who does the will of my Father who is in heaven. 22 On that day many will say to me, ‘Lord, Lord, did we not prophesy in your name, and cast out demons in your name, and do many mighty works in your name?’23 And then will I declare to them, ‘I never knew you; depart from me, you workers of lawlessness.’