הַנָּבִ֕יא אֲשֶׁ֥ר יִנָּבֵ֖א לְשָׁל֑וֹם בְּבֹא֙ דְּבַ֣ר הַנָּבִ֗יא יִוָּדַע֙ הַנָּבִ֔יא אֲשֶׁר־שְׁלָח֥וֹ יְהוָ֖ה בֶּאֱמֶֽת׃
The prophet that prophesieth of peace, when the word of the prophet shall come to pass, then shall the prophet be known, that the LORD hath truly sent him.’
Read halakhic rulings (Jewish law) on Jeremiah 28:9 from the Mishneh Torah and classical halakhic sources, free online.