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 16:6
Jesus said to them, "Pay attention and watch out for the leavening [effect] of the Pharisees and Sadducees."
Matthew 16:12
Then they understood that He was not telling them to watch out for the yeast in [physical] bread, but for the teaching of the Pharisees and Sadducees.
Mark 4:24
And He said to them, "Pay attention to what you are hearing from me. The standard you use in giving [to others] is the standard they will use on you, with even more added.
Mark 7:6-14
And He answered them, "Isaiah prophesied about you hypocrites very well when he wrote [Isa. 29:13], 'These people honor me with their lips [i.e., by what they say], but their heart is far from [honoring] me.
John 10:5
They will not follow a stranger, but will run from him, for they do not recognize the voice of strangers."
2 Corinthians 11:13-15
For such men are false apostles; they are deceitful workers, who disguise themselves as [true] apostles of Christ.
Ephesians 4:14
Then we will no longer be [spiritual] babies, tossed back and forth [by waves], and blown around by every wind of [false] teaching, [deceived] by the clever trickery of people using deceptive schemes.
1 Timothy 4:7
But you should have nothing to do with those worldly myths [See 1:4] and superstitious tales [often] told by old women. Instead, train yourself for living a godly life.
1 Timothy 6:3-5
If anyone teaches a different doctrine [i.e., from what has been urged above], and does not agree to [proclaim the] sound words of our Lord Jesus Christ and to teaching that is godly [i.e., in harmony with godliness],
2 Peter 2:1-2
But just as there were false prophets among the people before, there will also be false teachers among you [Christians]. They will privately teach harmful doctrines that destroy people [spiritually], by even denying [that Jesus is] the Master, [and thereby] destroying themselves quickly.
1 John 4:1
Loved ones, do not believe [the message of] every spirit [i.e., every person claiming to be a teacher], but test the spirits [i.e., require proof that they and their message are genuine] to see whether they represent God [or not], because many false prophets have begun circulating throughout the world.
2 John 1:10
If anyone comes to you [i.e., to your meetings] who does not bring this teaching [about Christ], you should not welcome him into your home or give him [any] greetings [i.e., suggesting approval or endorsement].
Revelation 2:2
I know about your deeds, your hard work and your perseverance. [I know] that you cannot tolerate wicked men and that you have tested those who call themselves apostles, but really are not, and found them to be liars.