אֲנִ֤י יָדַ֙עְתִּי֙ נְאֻם־יְהוָ֔ה עֶבְרָת֖וֹ וְלֹא־כֵ֑ן בַּדָּ֖יו לֹא־כֵ֥ן עָשֽׂוּ׃
I know his arrogancy, saith the LORD, That it is ill-founded; His boastings have wrought nothing well-founded.
Read halakhic rulings (Jewish law) on Jeremiah 48:30: and classical halakhic sources.