Therefore I tell you, whatever you ask in prayer, believe that you have received it, and it will be yours (Mk 11:24).
45 “Who then is the faithful and wise servant, whom his master has set over his household, to give them their food at the proper time? 46 Blessed is that servant whom his master will find so doing when he comes. 47 Truly, I say to you, he will set him over all his possessions. 48 But if that wicked servant says to himself, ‘My master is delayed,’ 49 and begins to beat his fellow servants and eats and drinks with drunkards, 50 the master of that servant will come on a day when he does not expect him and at an hour he does not know 51 and will cut him in pieces and put him with the hypocrites. In that place there will be weeping and gnashing of teeth (Mt 24:45-51; par. Lk 12:42-48).
i) I'd like to comment on the implications of this parable for the problem of unanswered prayer. The Markan verse is a typical example. There we have an unqualified promise. And it's not an isolated example. The NT contains similar promises. But, of course, in real life, prayer doesn't bat a thousand. Indeed, I doubt the batting average for most Christian at prayer is anywhere near that.
And not just for Christians in general. Do we really suppose the NT writers always got what they prayed for? I doubt it.
ii) So why doesn't God answer prayer more often? I've discussed this before, but I'd like to attack it from a fresh angle.
To begin with, it's a mistake to take certain truths to a logical extreme. That might sound counterintuitive to say. Indeed, I think it's a good thing to take abstract truths to a logical extreme.
However, that's not necessarily the case concerning some practical truths. That's because, especially in a fallen world, there's the problem of competing goods. Taking one practical truth as far as you can may lead to neglecting another practical truth. Sometimes we need to balance one off against another. They modify each other. Otherwise, taking two (or more) practical truths to a logical extreme may put them on a collision course.
iii) Although the parable is about the Parousia, it involves a general principle. How do people behave when they think no one is watching? For instance, you have people who behave differently under the gaze of a security camera. But if they forget about the security camera, or if they think it's off, then they may lose their moral inhibitions. If God was a hovering presence, many more people would feign to be God-fearing.
Or consider the cliché plot of trusting parents who must take a business trip out of town. They leave their home in the hands of their teenage kids. Of course their kids promise to be responsible in the absence of their parents. But when, due to unforeseen circumstances, the parents return early, they find a party in progress, with alcohol, drugs, hookups, and so on.
iv) Apropos (iii), unanswered prayer is a test of fidelity. Sometimes God plays the role of the absentee master in the parable. If God made his presence conspicuous by routinely answering prayer, that would be like having a security camera running in every room of the house. To be on your best behavior when you know the cops are watching you says nothing about your character. Consider what happens in a blackout or emergency when police are so overwhelmed that looters feel free to ransack stories with impunity.
God not answering prayer is like the master whose return flight is canceled due to inclement weather. Or so it seems. The security camera is off. Or so it seems.
Prayer promises are counterbalanced by unanswered prayer, because God's apparent absence is a test of fidelity. If God routinely answered prayer, that would function as an artificial deterrent to infidelity. You'd be faithful because you knew God was watching you. You'd know God was watching you due to the regular evidence of divine intercession. But to be faithful when God seems to be absent or indifferent is the acid test.