'Lose Heart' in the Bible

Now Jesus was telling the disciples a parable to make the point that at all times they ought to pray and not give up and lose heart,

Let us not grow weary or become discouraged in doing good, for at the proper time we will reap, if we do not give in.

So I ask you not to lose heart at my sufferings on your behalf, for they are your glory and honor.

And as for [the rest of] you, believers, do not grow tired or lose heart in doing good [but continue doing what is right without weakening].