1 John 4:1

Do not believe every spirit, beloved, but test the spirits to see if they come from God; for many false prophets have emerged in the world.

2 Peter 2:1

Still, false prophets did appear among the People, as among you also there will be false teachers, men who will insinuate destructive heresies, even disowning the Lord who ransomed them; they bring rapid destruction on themselves,

1 John 2:18

Children, it is the last hour. You have learned that 'Antichrist is coming.' Well, but many antichrists have appeared ??which makes us sure it is the last hour.

1 Thessalonians 5:21

but test them all, retaining what is good

Luke 12:57

And why do you not yourselves settle what is right?

Acts 17:11

where the people were more amenable than at Thessalonica; they were perfectly ready to receive the Word and made a daily study of the scriptures to see if it was really as Paul said.

1 Corinthians 12:10

one has prophecy, another the gift of distinguishing spirits, another the gift of 'tongues' in their variety, another the gift of interpreting 'tongues.'

1 Corinthians 14:29

Let only two or three prophets speak, while the rest exercise their judgment upon what is said.

1 Timothy 4:1

But in later days, the Spirit distinctly declares, certain people will rebel against the faith; they will listen to spirits of error and to the doctrines that daemons teach

2 John 1:7

I say this, because a number of impostors have emerged in the world, men who will not acknowledge the coming of Jesus Christ in the flesh; that marks the real 'impostor' and 'antichrist.'

Revelation 2:2

I know your doings, your hard work and your patient endurance; I know that you cannot bear wicked men, and that you have tested those who style themselves apostles (no apostles they!) and detected them to be liars;

Matthew 7:15-16

Beware of false prophets; they come to you with the garb of sheep but at heart they are ravenous wolves.

Matthew 24:4-5

Jesus replied, "Take care that no one misleads you;

Matthew 24:23-26

If anyone tells you at that time, 'Here is the Christ!' or, 'there he is!' do not believe it;

Mark 13:21

If anyone tells you at that time, 'Look, here is the Christ,' or, 'Look, there he is,' do not believe it;

Luke 21:8

He said, "Take care that you are not misled; for many will come in my name saying, 'I am he' and 'the time is near' ??do not go after them.

Acts 20:29

I know that when I am gone, fierce wolves will get in among you, and they will not spare the flock; yes.

Romans 16:18-19

Such creatures are no servants of Christ our Lord, they are slaves of their own base desires; with their plausible and pious talk they beguile the hearts of unsuspecting people. But surely not of you!

2 Timothy 3:13

Bad characters and impostors will go from bad to worse, deceiving others and deceived themselves;

Treasury of Scripture Knowledge

Summary

Beloved, believe not every spirit, but try the spirits whether they are of God: because many false prophets are gone out into the world.

Bible References

Believe not

Matthew 7:15
Beware of false prophets; they come to you with the garb of sheep but at heart they are ravenous wolves.
Matthew 24:4
Jesus replied, "Take care that no one misleads you;
Romans 16:18
Such creatures are no servants of Christ our Lord, they are slaves of their own base desires; with their plausible and pious talk they beguile the hearts of unsuspecting people. But surely not of you!
2 Peter 2:1
Still, false prophets did appear among the People, as among you also there will be false teachers, men who will insinuate destructive heresies, even disowning the Lord who ransomed them; they bring rapid destruction on themselves,

Try

Luke 12:57
And why do you not yourselves settle what is right?
Acts 17:11
where the people were more amenable than at Thessalonica; they were perfectly ready to receive the Word and made a daily study of the scriptures to see if it was really as Paul said.
Romans 16:19
Everyone has heard of your loyalty to the gospel; it makes me rejoice over you. Still, I want you to be experts in good and innocents in evil.
1 Corinthians 14:29
Let only two or three prophets speak, while the rest exercise their judgment upon what is said.
1 Thessalonians 5:21
but test them all, retaining what is good
Revelation 2:2
I know your doings, your hard work and your patient endurance; I know that you cannot bear wicked men, and that you have tested those who style themselves apostles (no apostles they!) and detected them to be liars;

General references

Matthew 24:11
Many false prophets will rise and mislead many.
John 8:47
He who belongs to God listens to the words of God; you do not listen to them, because you do not belong to God."
1 Corinthians 14:32
Prophets can control their own prophetic spirits,