Their apostolic way of life was marked by missionary fervor and simplicity.

apostolic 是由名词 apostle（使徒）加上形容词后缀 -ic 构成的形容词。apostle 来自希腊语 apostolos，意为"被派遣的人"，特指耶稣基督的十二门徒。 apostolic 意思是"使徒的、与使徒有关的"，形容像使徒那样具有传教热忱、生活简朴的特质。