The object of prayer is, neither to _inform_ God, as if he were not omniscient, nor to alter His eternal purposes, as if He were not unchangeable, nor to unsettle the established course of Nature, as if He were not "a God of order;" but simply to acknowledge His _dominion_ and our _dependence_, and to obtain from Him, in the way of His own appointment, the blessings of which we stand in need.
It is not unreasonable to believe that God, as the Governor of the world, will have some regard to the dispositions and actions of His responsible creatures, as a reason for dealing differently with those who own, and those who disown, His supremacy; and that He may require the use of certain means, such as the exercise of prayer, with the view of our obtaining from Him, in a way the most beneficial to ourselves, the blessings, whether temporal or spiritual, of which we stand in need.
For if we really be the creatures of God, and, as such, dependent on His providential bounty, and subject to His righteous government, it is self-evidently natural and right that we should, as intelligent and responsible beings, acknowledge His supreme dominion and our absolute dependence by supplicating the aids both of His providence and grace.
This is _our duty_, considering the relations which He sustains towards us; and if it be fit and proper that we should pray to God, if it be, in our circumstances, a duty which we owe to Him, then it is most reasonable to believe that it is equally fit and proper in God to have some respect to our prayers, and to deal with us differently according as we either observe or neglect this religious duty.
Prayer may be regarded in one or other of two distinct aspects: either as _a duty_, the observance or neglect of which must be followed, under a system of moral government, with different results; or simply as _a means_, the use of which is productive of certain effects which are made to depend on this special instrumentality.

And in either view, its "efficacy" may be affirmed on the same grounds on which we are wont to vindicate the use of _all other means_, and to enforce the observance of _all other duties_, in connection with the system of the Divine government.
3.

The efficacy of prayer, so far from being inconsistent with, is founded on, the immutability of the Divine purposes and the faithfulness of the Divine promises.

God's purposes are justly held, in all other cases, to include the _means_ as well as the _ends_; and they are often fulfilled through the instrumentality of "second causes." His purpose to provide for the wants of man and beast has reference not merely to the harvest which is the result, but also to the agricultural labor by which, instrumentally, the harvest is prepared.

May not "prayer" be also _a means_ ordained by God in the original constitution of the world, a means towards certain ends which are made dependent on its use?
If it be such a means, then its "efficacy" is established, in the only sense in which we are concerned to contend for it; while it is shown to be _no more inconsistent_ with the immutability of the Divine purposes, than any other system of _means or instruments_ that may be employed as subordinate agencies in the government of the world.