Jesus taught about continuing to believe that God will answer prayer.

Luke 18:1-8

18 Jesus told his disciples a parable to teach them that they always ought to pray confidently and not be discouraged if God does not immediately answer their prayers. 2 He said, “In a certain city there was a judge who did not revere God, and did not care about people, either. 3 There was a widow in that city who kept coming to him, saying, ‘Please decide what is just in the dispute between me and the man who is opposing me in court!’ 4 For a long time the judge refused to help her. But later he thought to himself, ‘I do not revere God and I do not care about people, 5 but this widow keeps bothering me! So I will make sure that she is treated justly. If I do not do that, she will exhaust me by continually coming to me!’ ” 6 Then the Lord Jesus said, “Even though the judge was not a righteous man, think carefully about what he said! 7 Similarly, ◄God will certainly show that what you have done has been right!/will God not show that what you have done has been right?► [RHQ] He will do this for you whom he has chosen. He will do this for you who pray earnestly to him night and day, asking him to help you. He may delay helping you. 8 But I tell you, some day he will show that what you did was right, and he will do it quickly. But when I, the one who came from heaven, return to earth, ◄there may not be many people who will still be trusting that I will vindicate them (OR, who will still be trusting in me)./will there be many people who will still be trusting that I will vindicate them (OR, who will still be trusting in me)?► [RHQ]”