Luther and Lewis

All the Psalms give Christians strength in suffering—that is, they comfort us in our afflictions, so that our backs do not break, but we continue in hope and patience. Thus He lends to all Christians. That is His way. Any who does know that does not know what sort of a king Christ is.—Martin Luther, Sermon upon the Feast of Sts. Peter and Paul

There are, no doubt, passages in the New Testament which may seem at first sight to promise an invariable granting of our prayers. But that cannot be what they really mean. For in the very heart of the story we meet a glaring instance to the contrary. In Gethsemane the holiest of all petitioners prayed three times that a certain cup might pass from Him. It did not. After that the idea that prayer is commended to us as a sort of infallible gimmick may be dismissed.—C. S. Lewis, Business of Heaven, p. 284.