Of... the Unity of the divine Nature, we shall have but little comparatively to say, because it is a subject on which much has been ably written, and is one which to thinking and philosophic minds is but little short of self-evident. The argument on the subject is commonly and very justly drawn from the evidences of oneness of design in the multiplied objects of creation.
There is a foundation for the argument from creation, because creation implies the fact of a creator, and because, looking at these objects in the light of their logical relation, creation does not contain anything which did not antecedently exist in the ideas of the creating Mind, so that creation, existing in the universe of objects around us, may justly be regarded as the out-going, the reflex, or if it be preferred, the shadows of the Infinite. And accordingly what God is in the eternal principles of his nature, including his Unity, is written not merely in the messages of Prophets and Apostles, but in his out-goings, in the emanations of Himself which exist in the things that are made, in the great robe of created forms and life which hangs as a garment around the brightness of his essential being. And there, as we read in accordance with the laws of our mental beings the multiplied facts of emanated or created existence, which are expressions of the oneness of thought and plan that lie hidden in the Source or Centre from which they come, our convictions become harmonized and consolidated in a particular direction; and at last it is impossible for us to doubt the Unity of that great Creative Centre. We cannot dwell, nor do we feel it to be necessary, upon the specific processes of thought by which this is done. Nevertheless, UNITY is the first word in the divine alphabet; and Nature, speaking in her silent voices, and writing her record in the book of the Absolute Religion, harmonizes with the Scriptures in saying, God is ONE God.
But this is not the only or the final word in the great facts of God’s existence. We proceed therefore to say, without however, confidently expecting an equal unanimity of opinion in regard to it, that the Divine Nature is dual, or two-fold, at the same time that it is one. This great mystery in the nature of the Divine Being is rendered possible by the great fact of Personality, which has this peculiarity, that, while it necessarily implies and includes existence, it may be regarded as something more than existence, because it is a fixed and discriminated modification of existence. The unity is in the existence; the duality which attaches to the same existence, and can never yield its claim to it, reveals itself in that real and indestructible modification of existence—that elemental fact of the universe, not easily explained, but which can never be ignored,—called Personality. It is upon this basis that the Absolute Religion, which cannot interpret itself independently of existing facts, harmonizes with the Scriptures in breaking up the desolateness of Unity and proclaiming the two-foldness or duality of the Divine Nature. And if we will but open our eyes, so significant are the facts that have relation to it, we cannot fail to see at least some evidences of it.
Some of the facts upon which our conclusions are founded are these: In every form or kind of existence which comes fully within the limits of human knowledge, we find that each form, while it is discriminated from every other form, reveals within the prescribed limits of its own existence the wonderful combination of unity of nature with a two-foldness or duality in the constitution of that nature. Take our common humanity as an example. No one can well deny that humanity is one in nature or being, while at the same time, without abrogating in any degree its unity and identity of nature, it is dualistic in personality. Man is not woman and woman is not man, and yet neither man nor woman is out of the limits of humanity. They stand revealed, to the comprehension of all true and candid judgment, forever one in the essential identicalness of being or nature, and yet forever discriminated by facts and relations which make them two in one. And our argument is, that God, in revealing this great fact in everything that is made, has revealed, in connection with the primal and essential unity in his own existence, the additional fact of duality. In other words, God is both Fatherhood and Motherhood.
To the mind impelled by the laws of its own being, that intuitionally accepts the great fact of Causation, and can read the inherent nature of the cause in the facts that flow from it, this, I think, is the inevitable conclusion. And from the eternal Fatherhood and Motherhood, furnishing, in their coexistent and co-operative duality, the only conceivable basis of such a result, all things proceed.
— edited from Absolute Religion (1873) Chapter 5.