Will not God grant justice to His elect who cry out to Him day and night?
I think one of the reasons Jesus tells us to pray persistently may very well be due to the way God created the brain to work-whenever we think of something, it is like chopping down a path in the woods to get somewhere. The more you walk that path, the smoother and wider it gets. Therefore the easier it becomes to walk it.
Prayer focuses our brain on its subject and takes our thoughts toward it. The more you think of something, the easier it is to think about, and consequently, the more difficult it is to NOT think about.
My son, don’t forget my teaching, but let your heart keep my commands; for they will bring you many days, a full life, and well being.
The way God set up life for humans to work best is given in his loving commands. They are not oppressive rules, but quite the opposite. They are freedom, giving road signs directing you toward abundant life that really is life.