Luke 11:10

But some one may seek to know, how it comes that they who pray are not heard? To which we must answer, that whose sets about seeking in the right way, omitting none of those things which avail to the obtaining of our requests, shall really receive what he has prayed to be given him. But if a man turns away from the object of a right petition, and asks not as it becomes him, he does not ask. And therefore it is, that when he does not receive, as is here promised, there is no falsehood. For so also when a master says, "Whoever will come to me, he shall receive the gift of instruction;" we understand it to imply a person going in real earnest to a master, that he may zealously and diligently devote himself to his teaching. Hence too James says, Ye ask and receive not, because ye ask amiss, (James 4:3.) namely, for the sake of vain pleasures. But some one will say, Nay, when men ask to obtain divine knowledge, and to recover their virtue they do not obtain? To which we must answer, that they sought not to receive the good things for themselves, but that thereby they might reap praise.

Now he who promises any thing ought to convey a hope of the thing promised, that obedience may follow commands, faith, promises. And therefore he adds, For every one that asketh receiveth.

The words, I say unto you, have the force of an oath. For God doth not lie, but whenever He makes known any thing to His hearers with an oath, he manifests the inexcusable littleness of our faith.