Deuteronomy 18:21

You may wonder: How shall we recognize that Jehovah did not speak this message?

1 Thessalonians 5:24

Faithful is he who calls you. He will also make it happen.

1 John 4:1-3

Beloved, do not believe every spirit. Test the spirits to see whether they are from God. This is because many false prophets have gone out into the world.

Revelation 2:2

I know your works, and your labor, and your patience. I also know how you cannot tolerate those who are evil. You tested those who say they are apostles. They are not apostles. You found 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
Faithful is he who calls you. He will also make it happen.
1 John 4:1
Beloved, do not believe every spirit. Test the spirits to see whether they are from God. This is because many false prophets have gone out into the world.
Revelation 2:2
I know your works, and your labor, and your patience. I also know how you cannot tolerate those who are evil. You tested those who say they are apostles. They are not apostles. You found them to be liars.