Albert Barnes Commentary Nehemiah 12:47

"And all Israel in the days of Zerubbabel, and in the days of Nehemiah, gave the portions of the singers and the porters, as every day required: and they set apart [that which was] for the Levites; and the Levites set apart [that which was] for the sons of Aaron." — Nehemiah 12:47 (ASV)

The intention is to compare the religious activity and strictness of Nehemiah’s time with that which had prevailed under Zerubbabel, as described by Ezra (Ezra 6:16), (Ezra 6:22). It is implied that the intermediate period had been a time of laxity.

They sanctified holy things ... — i.e., “the people paid their tithes regularly to the Levites, and the Levites paid the tithe of the tithes to the priests.”