New Revised Standard Version
You may say to yourself, “How can we recognize a word that the LORD has not spoken?”

Contemporary English Version
You may be asking yourselves, "How can we tell if a prophet's message really comes from the LORD?"

New American Bible
Should you say to yourselves, “How can we recognize that a word is one the LORD has not spoken?”,

Douay-Rheims Bible
And if in silent thought thou answer: How shall I know the word that the Lord hath not spoken?

And if in silent thought thou answer: How shall I know the word that the Lord hath not spoken?

1 Thessalonians 5:24 He is faithful who hath called you, who also will do it.

1 John 4:1-3 Dearly beloved, believe not every spirit, but try the spirits if they be of God: because many false prophets are gone out into the world. . . .

Revelation 2:2 I know thy works and thy labour and thy patience and how thou canst not bear them that are evil. And thou hast tried them who say they are apostles and are not: and hast found them liars: