ויאמר אלדד ומידד מתנבאים במחנה (בהעלותך יא:כז)

Medrash: הדא הוא דאמרינן (מגילה יח) מילה בסלע שתיקותא בתרי’ “This is what we say: ‘A word is worth one sela, but silence is worth two.’ What does it mean?

When Moshe Rabbeinu hit the stone, he was punished so that he would not be able to enter Eretz Yisroel; this was the prophecy of Eldad and Medad. But if Moshe had spoken to the stone, as Hashem commanded, he would have been able to enter the holy land, and the prophecy wouldn’t have been, and Eldad and Medad would have remained silent.  This is the translation of מילה בסלע – if Moshe had spoken to the stone שתיקותא בתרי – the two (Eldad and Medad) would have remained silent.