Ezra 8:21-23 New International Version (NIV)

21 There, by the Ahava Canal, I proclaimed a fast, so that we might humble ourselves before our God and ask him for a safe journey for us and our children, with all our possessions. 

Ezra and the people humbled themselves by prayer and fasting,

Ezra had told the king that he has a God who protects and now he didn’t want to go back and ask the king for protection.