1 John 4:1

My loved ones, do not put your faith in every spirit, but put them to the test, to see if they are from God: because a great number of false prophets have gone out into the world.

2 Peter 2:1

But there were false prophets among the people, as there will be false teachers among you, who will secretly put forward wrong teachings for your destruction, even turning away from the Lord who gave himself for them; whose destruction will come quickly, and they themselves will be the cause of it.

1 John 2:18

Little children, it is the last hour; and as you were given word that the Antichrist would come, so now a number of Antichrists have come to you; and by this we are certain that it is the last hour.

1 Thessalonians 5:21

Let all things be tested; keep to what is good;

Luke 12:57

And why are you, in your hearts, unable to be judges of what is right?

Acts 17:11

Now these were more noble than the Jews of Thessalonica, for they gave serious attention to the word, searching in the holy Writings every day, to see if these things were so.

1 Corinthians 12:10

And to another the power of working wonders; and to another the prophet's word; and to another the power of testing spirits; to another different sorts of tongues; and to another the power of making clear the sense of the tongues:

1 Corinthians 14:29

And let the prophets give their words, but not more than two or three, and let the others be judges of what they say.

1 Timothy 4:1

But the Spirit says clearly that in later times some will be turned away from the faith, giving their minds to spirits of deceit, and the teachings of evil spirits,

2 John 1:7

Because a number of false teachers have gone out into the world, who do not give witness that Jesus Christ came in the flesh. Such a one is a false teacher and Antichrist.

Revelation 2:2

I have knowledge of your doings, and of your hard work and long waiting, and that you will not put up with evil men, and have put to the test those who say they are Apostles and are not, and have seen that they are false;

Deuteronomy 13:1-5

If ever you have among you a prophet or a dreamer of dreams and he gives you a sign or a wonder,

Proverbs 14:15

The simple man has faith in every word, but the man of good sense gives thought to his footsteps.

Jeremiah 5:31

The prophets give false words and the priests give decisions by their direction; and my people are glad to have it so: and what will you do in the end?

Jeremiah 29:8-9

For this is what the Lord of armies, the God of Israel, has said: Do not let yourselves be tricked by the prophets who are among you, and the readers of signs, and give no attention to their dreams which they may have;

Matthew 7:15-16

Be on the watch for false prophets, who come to you in sheep's clothing, but inside they are cruel wolves.

Matthew 24:4-5

And Jesus said to them in answer, Take care that you are not tricked.

Matthew 24:23-26

Then if any man says to you, See, here is the Christ, or, Here; do not put faith in him;

Mark 13:21

And then if any man says to you, See, here is Christ; or, See, there; have no faith in it:

Luke 21:8

And he said, Take care that you are not tricked: for a number of people will come in my name, saying, I am he; and, The time is near: do not go after them.

Acts 20:29

I am conscious that after I am gone, evil wolves will come in among you, doing damage to the flock;

Romans 16:18-19

For such people are not servants of the Lord Christ, but of their stomachs; and by their smooth and well-said words the hearts of those who have no knowledge of evil are tricked.

2 Timothy 3:13

Evil and false men will become worse and worse, using deceit and themselves overcome by deceit.

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

Deuteronomy 13:1
If ever you have among you a prophet or a dreamer of dreams and he gives you a sign or a wonder,
Proverbs 14:15
The simple man has faith in every word, but the man of good sense gives thought to his footsteps.
Jeremiah 5:31
The prophets give false words and the priests give decisions by their direction; and my people are glad to have it so: and what will you do in the end?
Jeremiah 29:8
For this is what the Lord of armies, the God of Israel, has said: Do not let yourselves be tricked by the prophets who are among you, and the readers of signs, and give no attention to their dreams which they may have;
Matthew 7:15
Be on the watch for false prophets, who come to you in sheep's clothing, but inside they are cruel wolves.
Matthew 24:4
And Jesus said to them in answer, Take care that you are not tricked.
Romans 16:18
For such people are not servants of the Lord Christ, but of their stomachs; and by their smooth and well-said words the hearts of those who have no knowledge of evil are tricked.
2 Peter 2:1
But there were false prophets among the people, as there will be false teachers among you, who will secretly put forward wrong teachings for your destruction, even turning away from the Lord who gave himself for them; whose destruction will come quickly, and they themselves will be the cause of it.

Try

Luke 12:57
And why are you, in your hearts, unable to be judges of what is right?
Acts 17:11
Now these were more noble than the Jews of Thessalonica, for they gave serious attention to the word, searching in the holy Writings every day, to see if these things were so.
Romans 16:19
For all have knowledge of how you do what you are ordered. For this reason I have joy in you, but it is my desire that you may be wise in what is good, and without knowledge of evil.
1 Corinthians 14:29
And let the prophets give their words, but not more than two or three, and let the others be judges of what they say.
1 Thessalonians 5:21
Let all things be tested; keep to what is good;
Revelation 2:2
I have knowledge of your doings, and of your hard work and long waiting, and that you will not put up with evil men, and have put to the test those who say they are Apostles and are not, and have seen that they are false;

General references

Deuteronomy 18:21
And if you say in your hearts, How are we to be certain that the word does not come from the Lord?
Proverbs 19:27
A son who no longer gives attention to teaching is turned away from the words of knowledge.
Matthew 24:11
And a number of false prophets will come, causing error.
John 8:47
He who is a child of God gives ear to the words of God: your ears are not open to them because you are not from God.
1 Corinthians 14:32
And the spirits of the prophets are controlled by the prophets;

Basic English, produced by Mr C. K. Ogden of the Orthological Institute - public domain