וְסִכְסַכְתִּ֤י מִצְרַ֙יִם֙ בְּמִצְרַ֔יִם וְנִלְחֲמ֥וּ אִישׁ־בְּאָחִ֖יו וְאִ֣ישׁ בְּרֵעֵ֑הוּ עִ֣יר בְּעִ֔יר מַמְלָכָ֖ה בְּמַמְלָכָֽה׃
And I will spur Egypt against Egypt; And they shall fight every one against his brother, And everyone against his neighbour; City against city, and kingdom against kingdom.
Read halakhic rulings (Jewish law) on Isaiah 19:2: and classical halakhic sources.