The little Bible college in northern Ghana didn’t look impressive—just a tin-roofed cinder-block building and a handful of students. Yet Bob Hayes poured his life into those students. He gave them leadership roles and encouraged them to preach and teach, despite their occasional reluctance. Bob passed away years ago, but dozens of thriving churches, schools, and two additional Bible institutes have sprung up across Ghana—all started by graduates of that humble school.

During the reign of King Artaxerxes (465–424 bc), Ezra the scribe assembled a band of Jewish exiles to return to Jerusalem. But Ezra found no Levites among them (Ezra…