1 Thessalonians 5:24

He who calls you is faithful, he will do this.

1 John 4:1-3

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.

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;

Treasury of Scripture Knowledge

Summary

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

Bible References

General references

1 Thessalonians 5:24
He who calls you is faithful, he will do this.
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.
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;