ESV scriptures about what will happen to false prophets and why they are an issue.
Due 18:20-22 But the prophet who presumes to speak a word in my name that I have not commanded him to speak, or who speaks in the name of other gods, that same prophet shall die.’ And if you say in your heart, ‘How may we know the word that the Lord has not spoken?’ when a prophet speaks in the name of the Lord, if the word does not come to pass or come true, that is a word that the Lord has not spoken; the prophet has spoken it presumptuously. You need not be afraid of him.
Matt 7:15-23 “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 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.’“
2 Cor 11:13-15 “For such men are false apostles, deceitful workmen, disguising themselves as apostles of Christ. 14 And no wonder, for even Satan disguises himself as an angel of light. 15 So it is no surprise if his servants, also, disguise themselves as servants of righteousness. Their end will correspond to their deeds.”
Mark 13:22 “For false christs and false prophets will arise and perform signs and wonders, to lead astray, if possible, the elect.”