1 John 4:1

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

2 Peter 2:1

As there were false prophets among the people of Israel, there will likewise be false doctors among you, who by introducing pernicious sects, and by renouncing the Lord, who bought them, will bring upon themselves swift destruction.

1 John 2:18

Dear children, the last time is come: as ye have heard that antichrist was to come, accordingly many antichrists have already appeared; whereby we know that we are now in the last times.

1 Thessalonians 5:21

bring every thing to the test: if it be proof, abide by that:

Luke 12:57

why can't you judge what is proper to be done in your own affairs.

Acts 17:11

the Jews there were of a more generous temper than those of Thessalonica: for they very readily embrac'd their doctrine, and daily examin'd, whether it was conformable to the scriptures.

1 Corinthians 12:10

to another the working of miracles; to another prophecy, to another discerning of spirits; to another diversity of languages; to another the interpretation of languages.

1 Corinthians 14:29

of the prophets let but two or three speak by turns, and let the others deliberate.

1 Timothy 4:1

Now the spirit says expresly, that in the latter times some shall abandon the faith, by giving credit to seducing spirits, and the doctrine concerning demons;

2 John 1:7

For there are many impostors started up in the world, who will not own that Jesus Christ was incarnate. such a one is an impostor and an anti-christ.

Revelation 2:2

I know thy works, thy labour, and thy patience, and that thou canst not bear those who are evil: thou hast tried those who say they are apostles, but are not; and hast found them lyars:

Matthew 7:15-16

Beware of false prophets, who to outward appearance are sheep, but inwardly they are ravenous wolves.

Matthew 24:4-5

Jesus answered them, take care not to be deceived by any one:

Matthew 24:23-26

Then if any shall cry, the Messiah is here, or he is there: give no credit to it.

Mark 13:21

Then if any one shall say to you, Christ is here, or, he is there, don't believe it.

Luke 21:8

he answered, take care, that you be not seduced: for many shall come in my name, saying, I am the Christ. it won't be long e'er this happens, therefore do not follow them.

Acts 20:29

for I know when I am gone, you will be oppress'd by wolves, that will not spare the flock.

Romans 16:18-19

for such as these serve not our Lord Jesus Christ, but their own selfishness; and by flourish and flattery, deceive the open-hearted simple.

2 Timothy 3:13

as for these impious impostors, they will go on from bad to worse, seducing others, and deluding 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, who to outward appearance are sheep, but inwardly they are ravenous wolves.
Matthew 24:4
Jesus answered them, take care not to be deceived by any one:
Romans 16:18
for such as these serve not our Lord Jesus Christ, but their own selfishness; and by flourish and flattery, deceive the open-hearted simple.
2 Peter 2:1
As there were false prophets among the people of Israel, there will likewise be false doctors among you, who by introducing pernicious sects, and by renouncing the Lord, who bought them, will bring upon themselves swift destruction.

Try

Luke 12:57
why can't you judge what is proper to be done in your own affairs.
Acts 17:11
the Jews there were of a more generous temper than those of Thessalonica: for they very readily embrac'd their doctrine, and daily examin'd, whether it was conformable to the scriptures.
Romans 16:19
your christianity is very well known in the world. I am glad therefore on your behalf: but yet I would have you as expert in that which is good, as unpractis'd in what is evil.
1 Corinthians 14:29
of the prophets let but two or three speak by turns, and let the others deliberate.
1 Thessalonians 5:21
bring every thing to the test: if it be proof, abide by that:
Revelation 2:2
I know thy works, thy labour, and thy patience, and that thou canst not bear those who are evil: thou hast tried those who say they are apostles, but are not; and hast found them lyars:

General references

Matthew 24:11
many false prophets shall rise, and shall deceive many.
John 8:47
he that is of God, does therefore observe what God says: which you do not observe, because ye are not of God.
1 Corinthians 14:32
the prophetic gifts are to be subservient to the prophets.