Then Jesus told them a parable about their need to pray at all times and not lose heart: — Luke 18:1

Jesus told His disciples they should always pray and not lose heart. He didn't say this because prayer is a duty to check off; prayer is how you stay alive. The persistent widow kept coming until the unjust judge gave in — how much more will your Father hear you? Jacob wrestled until daybreak and wouldn't let go. That's the kind of praying that doesn't quit.