Luke does something he almost never does here. He tells you the point of the parable before he tells the parable.
Jesus told them a parable about their need to pray at all times and not lose heart. The interpretation comes first, which suggests Luke did not want anyone missing it.
Sit with the assumption buried in that sentence. Losing heart is treated as the expected danger. Not unbelief exactly, not rebellion, just the slow quiet erosion of people who prayed for a while and then stopped because nothing seemed to be happening.
That is a gentler diagnosis than most of us give ourselves. When prayer goes flat we tend to assume something is spiritually wrong with us. Jesus seems to treat it as an ordinary hazard that needs guarding against, the way you would guard against getting tired on a long walk.
The instruction is not to feel more. It is simply not to stop.
