And will not God give justice to his elect, who cry to him day and night? Will he delay long over them? I tell you, he will give justice to them speedily. Nevertheless, when the Son of Man comes, will he find faith on earth?
Luke 18:7-8

The point isn't that God makes you wait until you've asked enough times and proven your seriousness through persistence, but that he doesn't make you wait any longer than is necessary to fulfill the needs of the kingdom.