The efficacy of prayer is one of the last things that a scientific naturalist should question, if he is at the same time a theist. Prayer is itself one of the laws of nature, and one of those that show in the finest way how higher laws override and modify those that are lower. The young ravens, we are told, cry to God; and so they literally do; and their cry is answered, for the parent-ravens, cruel and voracious, under the impulse of a God-given instinct range over land and water and exhaust every energy that they may satisfy that cry. The bleat of the lamb will not only meet with response from the mother-ewe, but will even exercise a physiological effect in promoting the secretion of milk in her udder. The mother who hears the cry of her child, crushed under some weighty thing which has fallen on it, will never pause to consider that it is the law of gravitation which has caused the accident; she will defy the law of gravitation, and if necessary will pray any one who is near to help her. Prayer, in short, is a natural power so important that without it the young of most of the higher animals would have little chance of life; and it triumphs over almost every other natural law which may stand in its way. If, then, irrational animals can overcome the forces of dead nature in answer to prayer; if man himself, in answer to the cry of distress, can do things in ordinary circumstances almost impossible,--how foolish is it to suppose that this link of connection cannot subsist between God and his rational offspring! One wonders that any man of science should for a moment entertain such an idea, if, indeed, he has any belief whatever in the existence of a God.
There is another aspect of prayer insisted on in revelation on which the observation of nature throws some light. In the case of animals, there must be a certain relation between the one that prays and the one that answers--a filial relation, perhaps--and in any case there must be a correspondence between the language of prayer and the emotions of the creature appealed to. Except in a few cases where human training has modified instinct, the cry of one species of animal awakes no response in another of a different kind. So prayer to God must be in the Spirit of God. It must also be the cry of real need, and with reference to needs which have his sympathy. There is a prayer which never reaches God, or which is even an abomination to him; and there is prayer prompted by the indwelling Spirit of God, which cannot be uttered in human words, yet will surely be answered. All this is so perfectly in accordance with natural analogies, that it strikes one acquainted with nature as almost a matter of course.