Mark 13:6
"Be ye watchful lest any one mislead you. Many will come in my name, saying, 'I am he,' and will mislead many.
Mark 13:22
for false Christs and false prophets will arise and will show signs and wonders, to lead astray the very chosen, if they can.
Matthew 24:5
for many will come in my name saying, 'I am the Christ,' and will mislead many.
Matthew 24:11
Many false prophets will rise up and mislead many;
Matthew 24:23-24
"If at that time any one should say to you, 'See, here is the Christ!' or 'There he is!' believe him not.
John 5:43
"I am come in the name of my Father and you do not receive me. If another comes in his own name, him you will receive.
John 8:24
"That is why I said that you would die in your sins. For if you do not believe that I am He, you will die in your sins."
Acts 5:36-39
"Years ago Theudas arose, claiming to be somebody, and was joined by about four hundred men. He was killed, and all of his followers dispersed and annihilated.
1 John 4:1
Do not believe every spirit, beloved, but test the spirits to see whether they are of God; for many false prophets are gone out into the world.