Children have this special ‘gift’ of… asking until they get what they want!
We know it, and parents especially know it from experience!
Asking, begging, demanding – with screams and tears if need be – children are past masters at that.
I suppose that we, grown-ups, would not judge this to be the proper attitude when…
we come to God!
Well, perhaps not the screams and tears, but the perseverance in asking, DEFINITELY!
This is precisely the point of Jesus’ parable in today’s gospel text (Lk.11:1-13).
A friend waking up his friend to ask for his help and insisting, keeping on begging for what he needs:
this is exactly what Jesus gives us as an example to follow.
Of course, this supposes that, first of all, we consider God as a Friend – no less!
And then that we remain absolutely sure that he cannot not give us what we are in need of.
And, in the process, a touch of bargaining is not excluded –
the first reading is clear on this as well (Gn.18:20-32).
Abraham shows himself very skilled in praising God as a way of obtaining what he wants! 
His insistence and his on-going pleading are truly inspiring!
“Will the judge of the whole earth not administer justice?”
And while admitting that he is ‘bold’ Abraham, with due respect, dares telling God what he should not do!
“Do not think of doing such a thing!”
I personally think that, as guidelines on ‘How to Pray’, these readings can hardly be surpassed!
Note: Another reflections is available on a similar theme in French at: https://image-i-nations.com/17e-dimanche-de-lannee-c-2019/