'Lose Heart' in the Bible

Their insults are painful and make me lose heart; I look for sympathy, but receive none, for comforters, but find none.

The people of Damascus will lose heart and turn to flee. Panic will grip them. Pain and anguish will seize them like a woman in labor.

Then Jesus told them a parable to show them they should always pray and not lose heart.

For this reason I ask you not to lose heart because of what I am suffering for you, which is your glory.