Ezra 2:40

the priests...The Levites: Only seventy-four Levites returned to Jerusalem, which was a very low number. Ezra later worked hard to bring thirty-eight more with him (see study note on Ezra 8:18).

This chapter is Ezra's first major digression from the main story. The returning exiles needed to identify true Jews to maintain their community identity and theological purity. This helped them know whom they could marry and who could worship at the temple. This list is not the initial list of all Jews who returned to Jerusalem (compare Nehemiah 7:6–73). Instead, it is a slightly later list, created after Sheshbazzar died, of people who had settled in their towns.