'Fasted' in the Bible

Then they mourned and wept and fasted over Saul and Jonathan his son until the evening, [as well] as over the people of Yahweh and over the house of Israel because they had fallen by the sword.

David pleaded [with] God on behalf of the boy and David fasted. He went to spend the night and lay upon the ground.

Then his servants said to him, "What [is] this thing that you have done? While the child [was] alive, you fasted and wept; [now] that the child has died, you get up and eat food!"

He said, "When the child [was] still alive, I fasted and I wept because I thought, 'Who knows? Yahweh may have mercy on me that the child will live.'