Esther 4:
That was a nice place for Mordecai to mention God's deliverance, but he didn't.12 When Esther’s words were relayed to Mordecai, 13he sent back to her this reply: “Do not imagine that because you are in the king’s palace you alone will escape the fate of all the Jews. 14 For if you remain silent at this time, relief and deliverance for the Jews will arise from another place, but you and your father’s house will perish. And who knows if perhaps you have come to the kingdom for such a time as this?”
Fasting was often associated with praying. That's a natural place for Esther to mention praying, but she didn't.15 Then Esther sent this reply to Mordecai: 16“Go and assemble all the Jews who can be found in Susa, and fast for me.
Ezra was around the time of Esther. His wording was the usual, Ezra 8:Do not eat or drink for three days, night or day, and I and my maidens will fast as you do. After that, I will go to the king, even though it is against the law. And if I perish, I perish!”
Another example is Nehemiah1:23 So we fasted and petitioned our God about this, and he answered our prayer.
4 When I heard these things, I sat down and wept. For some days I mourned and fasted and prayed before the God of heaven.