וַיֹּ֤אמֶר אֵלָיו֙ אֱד֔וֹם לֹ֥א תַעֲבֹ֖ר בִּ֑י פֶּן־בַּחֶ֖רֶב אֵצֵ֥א לִקְרָאתֶֽךָ׃
And Edom said unto him: ‘Thou shalt not pass through me, lest I come out with the sword against thee.’
Read halakhic rulings (Jewish law) on Numbers 20:18: and classical halakhic sources.