This passage tells about the great thanksgiving ceremony of the people of Israel when God helped them to rebuild the walls. The rulers, the priests' sons, the priests -- all were involved in leading the special occasion. All the leaders and rulers of the people led the time of thanksgiving and rejoicing.
Musical instruments were brought. A big choir came to sing, and they sang aloud. There were great sacrifices and rejoicing because God had made them to rejoice with great joy so that the sound of their rejoicing was heard afar off.
Today is the national day of prayer. Wouldn't it be wonderful if the foundations and protective walls (spiritually speaking) of our nation were rebuilt, and we could have such a rejoicing that it would be heard afar off? Wouldn't it be wonderful if our national and spiritual leaders were the ones who went first and led in this event? May God make such a day possible!