When Elijah was summoned from Zarephath to resume his public work, his marching orders were capped by the specific promise of rain: "Go, show thyself unto Ahab; and I will send rain upon the earth" (1 Kings 18:1). To natural reason this might have seemed to render prayer unnecessary. Would not God fulfill His promise, and send the rain, altogether irrespective of further prayer? But Elijah's spiritual instincts argued otherwise, and more truly.
God's promises are given, not to restrain, but to incite to prayer. They show the direction in which we may ask, and the extent to which we may expect an answer. They are the mold into which we may pour our fervid spirits without fear. They are the signed check, made payable to order, which we must endorse and present for payment. Though the Bible is crowded with golden promises from board to board, yet will they be inoperative until we turn them into prayer. It is not our province to argue the reasonableness of this; it is enough to argue and enforce it. Why should it not be sufficient to silence all questions by saying that we have here reached one of the primal laws of the spiritual world, as simple, as certain, as universal, as any that obtain in the world of nature? Promises of abundant harvest smile to the husbandman from earth and sky, but he knows that they will not be realized unless he puts into operation the laws and processes of agriculture. As he does so, it is not necessary for his success that he should understand the why and wherefore; it is enough for him to do his little part, and he finds that every promise is fulfilled in the produce shed at his feet from Nature's golden horn.
When, therefore, we are asked why men should pray, and how prayer avails, we are not careful to answer more than this: "Prayer is the instinct of the religious life; it is one of the first principles of the spiritual world." It is clearly taught in the Word of God to be prevalent with the Almighty. It has been practiced by the noblest and saintliest of men, who have testified to its certain efficacy. Our Lord Jesus not only practiced it, but proclaimed its value in words which have been plunged a myriad times into the crucible of experience and are as true today as ever: "Ask, and it shall be given you; seek, and ye shall find; knock, and it shall be opened unto you" (Luke 11:9). We are content, therefore, to pray, though we are as ignorant of the philosophy of the modus operandi of prayer as we are of any natural law. We find it no dreamy reverie or sweet sentimentality, but a practical, living force. Whenever we stand by the altar of incense, we become aware of the angel of the Lord standing hard by, and saying, "Fear not, O man greatly beloved! thy prayer is heard."
When your child was a toddling, lisping babe, he asked many things wholly incompatible with your nature and its own welfare; but as the years have passed, increasing experience has molded your child's requests into shapes suggested by yourself. So, as we know more of God through His promises, we are staid from asking what He cannot give and led to set our hearts on things which lie on His open palm waiting to be taken by the hand of an appropriating faith. This is why all prayer, like Elijah's, should be based on promise. We stand on a foundation of adamant and have an irresistible purchase with God when we can put our finger on His own promise and say, "Do as Thou hast said." F. B. Meyer