Chapter twelve begins with a couple more lists. First, in vv.1-11 we see the priests and the Levites who came up with Zerubbabel the son of Shealtiel (v.1). Then, in vv.12-21 we see a list of priests in the days of Joiakim, and finally in vv.22-26 Levites in the reign of Darius the Persian. This section finishes with a time-stamp of sorts in v.26.
The Levites now come to the fore, so to speak, and they lead the people in musical worship of thanksgiving with an array of instruments (v.27). The singers are mentioned separately and, so I read, they would have needed to be pretty good singers in order to lead the people in musical worship (a joyful noise, yes, but a tuneful and joyful noise).
The first big task in dedicating the wall we then see in v.30,
When the priests and Levites had purified themselves, they purified the people, the gates, and the wall.
First, the priests and Levites purified themselves, then they purified the people, and finally the gates, and the wall. The rest of the chapter (vv.31-47) is a recollection of the dedication of the wall and the associated thanksgiving, but it is here in the purification that we want to take something and apply it for ourselves today.
We see that first, before interacting with and leading others, the priests and Levites purified themselves. You cannot, well should not, lead others if you are not leading yourself. The result is empty, hollow, and shallow leadership. First, lead yourself. Purify yourself. There are many New Covenant ways to do this, try 1 John 1.9 as one example.
Whatever you find in the New Testament regarding purity and putting yourself in the right mindset and mentality before God will, I am going to suggest to you, find its root in Jesus. Under the Old Covenant, we could never work our way to becoming good enough or pure enough. Here, in Nehemiah 12, the people had to constantly work at these purification rituals and had to constantly work at this concern (v.45).
For you and for me, we need not do this. We need not constantly work at this concern – am I pure enough, am I good enough, am I in the right state, ceremonially, to come before God? The finished work of Jesus on the cross, His death and resurrection and your faith therein means, that should you accept and affirm this, should you submit and commit to this, you are as pure before God as you will ever be.
For a point to ponder today, try reading Matthew 26.26-30, and Hebrews 9.11-28. Then, as we see here in Nehemiah 12, rejoice with great joy!