Deuteronomy 18:21

If you say in your heart, ‘How will we know and recognize the word which the Lord has not spoken?’

1 Thessalonians 5:24

Faithful and absolutely trustworthy is He who is calling you [to Himself for your salvation], and He will do it [He will fulfill His call by making you holy, guarding you, watching over you, and protecting you as His own].

1 John 4:1-3

Beloved, do not believe every spirit [speaking through a self-proclaimed prophet]; instead test the spirits to see whether they are from God, because many false prophets and teachers have gone out into the world.

Revelation 2:2

‘I know your deeds and your toil, and your patient endurance, and that you cannot tolerate those who are evil, and have tested and critically appraised those who call themselves apostles (special messengers, personally chosen representatives, of Christ), and [in fact] are not, and have found them to be liars and impostors;

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 and absolutely trustworthy is He who is calling you [to Himself for your salvation], and He will do it [He will fulfill His call by making you holy, guarding you, watching over you, and protecting you as His own].
1 John 4:1
Beloved, do not believe every spirit [speaking through a self-proclaimed prophet]; instead test the spirits to see whether they are from God, because many false prophets and teachers have gone out into the world.
Revelation 2:2
‘I know your deeds and your toil, and your patient endurance, and that you cannot tolerate those who are evil, and have tested and critically appraised those who call themselves apostles (special messengers, personally chosen representatives, of Christ), and [in fact] are not, and have found them to be liars and impostors;