מִן־בְּנֵי־פֶ֗רֶץ הָרֹ֛אשׁ לְכָל־שָׂרֵ֥י הַצְּבָא֖וֹת לַחֹ֥דֶשׁ הָרִאשֽׁוֹן׃
他是法勒斯的子孫，作眾軍長的首領，管理正月的班。
Rashi
the chief of all the leaders of the hosts Jashabeam was [one] of the sons of Perez, and he was the chief of all the twelve leaders, and because he was [one] of the sons of Perez, David appointed him chief.