Matthew 7:15
"Look out for deceiving prophets, who approach you wearing sheep's clothing, but who are [actually] starving wolves in their hearts.
Matthew 24:11
And many false prophets will appear and will lead many people away [from the truth].
Matthew 24:24
For false Christs and false prophets will appear and they will perform great [miraculous] signs and [supernatural] wonders in order to lead astray even the elect [i.e., God's people], if possible.
2 Timothy 3:8
These people oppose the truth just like Jannes and Jambres opposed Moses. They have corrupt minds and are worthless as far as the faith is concerned.
2 Timothy 4:14-15
Alexander the metal worker did me much harm; the Lord will repay him for what he did.
1 John 5:16
If anyone [of you] observes his brother [or sister] sinning [in a way that would not lead] to [spiritual] death, he should ask [God, in prayer, to help that person], and God will give him [spiritual] life, [that is], to such ones, provided their sin is not leading to [spiritual] death. There is such a sin that leads to [spiritual] death. [See Heb. 6:4-6; I Tim. 5:6; Heb. 10:26-27; II Pet. 2:20-22]. I am not suggesting that you should ask [God, in prayer] about such a situation.
Revelation 19:20
But the beast was captured, along with the false prophet [See 16:13], who performed [supernatural] signs in his presence. [He had performed these signs] to deceive those who had received the mark of the beast and those who worshiped his statue. [See 13:15-16]. The beast and the false prophet were both thrown alive into the lake of fire that burns with sulphur.