Nehemiah 12:30

And the priests and the Levites purified themselves, and purified the people, and the gates, and the wall.

The verse belongs to the dedication of the rebuilt and finished wall of Jerusalem after the return from Babylonian captivity, taking place on Nehemiah's return to Jerusalem after months at the Persian court, in the last reform covered by Nehemiah 11-13 and dated about 446-408. The priests and the Levites first purified themselves and then purified the people, the gates, and the wall. Priests, Levites, and singers were gathered from the cities, villages, and plain country of Judah to lead the dedication with gladness, thanksgiving, and music with cymbals, psalteries, and harps. That keeping of the dedication included great sacrifices and rejoicing because God had made them rejoice, with wives and children joining until the joy of Jerusalem was heard far off.

This cleansing left all purified and prepared for the day of dedication and for the city's worship and service. Nehemiah worked always with the highest good of Jerusalem in mind, impatient over slackness in the work of God and indignant over sin against God in uniting with heathen peoples and even bringing them into the temple itself. His zealous manner as a reformer is not always to be copied, yet under his circumstances he is not to be condemned, for he stood for God, the city was the Lord's city, and the people were the Lord's people. True thanksgiving includes moral cleansing of leaders and people together with practical material giving in sacrifices and offerings, so the verse provides a pattern for a Thanksgiving celebration.