What does Nehemiah 9:1 mean?

On the twenty-fourth day of that same month, the Israelites gathered together. They were fasting, wearing rough clothes, and had put dirt on their heads as a sign of sadness. Nehemiah 9:1 - Modern Text Bible

(The people came together to show they were sorry for their sins. Fasting and wearing sackcloth were ways to express grief and humility before God.)