וַיִּתְפֹּ֣שׂ אֲחִיָּ֔ה בַּשַּׂלְמָ֥ה הַחֲדָשָׁ֖ה אֲשֶׁ֣ר עָלָ֑יו וַיִּ֨קְרָעֶ֔הָ שְׁנֵ֥ים עָשָׂ֖ר קְרָעִֽים׃
And Ahijah laid hold of the new garment that was on him, and rent it in twelve pieces.
Read halakhic rulings (Jewish law) on I Kings 11:30: and classical halakhic sources.