הַֽמְשֹׁרְרִ֑ים בְּנֵ֣י אָסָ֔ף מֵאָ֖ה עֶשְׂרִ֥ים וּשְׁמֹנָֽה׃ (פ)
The singers: the children of Asaph, a hundred twenty and eight.
Rashi on Ezra
The singers The Levites who were singers, and likewise, the gatekeepers are Levites who were gatekeepers of the gates of the Temple.