Deuteronomy 18:21

If you say in your heart, "How shall we know the word which Yahweh has not spoken?"

1 Thessalonians 5:24

He who calls you is faithful, who will also do it.

1 John 4:1-3

Beloved, don't believe every spirit, but test the spirits, whether they are of God, because many false prophets have gone out into the world.

Revelation 2:2

"I know your works, and your toil and perseverance, and that you can't tolerate evil men, and have tested those who call themselves apostles, and they are not, and found them false.

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, who will also do it.
1 John 4:1
Beloved, don't believe every spirit, but test the spirits, whether they are of God, because many false prophets have gone out into the world.
Revelation 2:2
"I know your works, and your toil and perseverance, and that you can't tolerate evil men, and have tested those who call themselves apostles, and they are not, and found them false.