EXTRA · Side-ring · Parashas Shoftim · Passuk 18:21
And if you say in your heart, ‘How shall we know the word that the Eternal has not spoken?’
Chazal / classical source (beyond TT-numbered main-ring units): Sanhedrin 89a related.
Lemma: אֲשֶׁר לֹא דִבְּרוֹ ה׳.
Sefaria — Sanhedrin 89a related
English: ‘That the Eternal has not spoken’ – this is one who prophesies what was not said to him.
Derash defining the false claim (Bavli) — the problem is a word that never issued from Hashem.
The critical question is how to detect a message that Hashem never spoke; the subsequent verse gives the practical test of non-fulfillment.