'Fasted' in the Bible

They mourned, and wept, and fasted until evening, for Saul, and for Jonathan his son, and for the people of Yahweh, and for the house of Israel; because they were fallen by the sword.

David therefore begged God for the child; and David fasted, and went in, and lay all night on the earth.

Then his servants said to him, "What is this that you have done? You fasted and wept for the child while he was alive; but when the child was dead, you rose up and ate bread."

He said, "While the child was yet alive, I fasted and wept; for I said, 'Who knows whether Yahweh will not be gracious to me, that the child may live?'