All persons whose fullness of faith has brought them into the state of union with God, know this to be the case. They know (without knowing how they know it) that the movement of desire in their own souls, arising sometimes under remarkable circumstances and in a remarkable way, is the continuation, the distant but affiliated throbbing, of the great heart of the universe. And with such a conviction existing in their minds, it obviously becomes easy, and, perhaps we may say, necessary for them, to exercise that particular form of faith which is appropriate to their state of desire. Having, therefore, a desire for a particular thing, and believing that this desire is only the vibration from the great center, the finite repetition of the infinite desire, they cannot doubt that there will be a manifestation of God, correspondent to that form of inward feeling which exists in him as well as in themselves.
If what has been said is correct, then it may properly be added, that there is something not only impressive but sublime, and almost terrible, in a holy man's prayer; whether it take the form of supplication, or of blessing, or of praise. That praying voice which thou hearest, broken though it may be with weakness and trembling with age, is not more the voice of man than of God. Oh, do not trifle with it, if thou wouldst not trifle with God himself! Uttered in these last days, it is nevertheless true, that, in its attributes of origin and power, it is the voice of Abraham, of Moses, of Daniel; — men who had power with God, because God had power with them. It is the chain of communication between two worlds; the circumference, showing the light and heat of the center. It brings down the sunlight of God's favor, or the lightning of his displeasure. If it curses thee, then thou art cursed; if it blesses thee, then thou art blessed. If it expresses itself in pity, then the tear of compassion is falling upon thee from the omniscient eye. Listen reverently, therefore, to the good man's prayer. God is in it.
— edited from A Treatise on Divine Union (1851) Part 7, Chapter 11.