1 John 4:1-3

Beloved, do not believe every spirit, but try the spirits, whether they be from God; because many false prophets are gone forth into the world.

Revelation 2:2

I know your works, and your labor, and your patience; and that you can not bear those who are evil: and you have tried those who say they are Apostles, and are not, and have found them liars;

Treasury of Scripture Knowledge

Summary

And if thou say in thine heart, How shall we know the word which the LORD hath not spoken?

General references

Bible References

General references

1 John 4:1
Beloved, do not believe every spirit, but try the spirits, whether they be from God; because many false prophets are gone forth into the world.
Revelation 2:2
I know your works, and your labor, and your patience; and that you can not bear those who are evil: and you have tried those who say they are Apostles, and are not, and have found them liars;