Selection from True Christian Religion ~ Emanuel Swedenborg
there is in all the world no nation possessing religion and sound reason that does not acknowledge a God, and that God is One. As a consequence of the Divine influx into the souls of men, treated of just above, there is in every man an internal dictate that there is a God and that He is One. And yet there are some who deny God, and some who acknowledge nature as god, and some who acknowledge more gods than one, and some who worship images as gods; which is possible because such have blocked up the interiors of their reason or understanding with worldly and corporeal things. thereby obliterating their first or childhood idea respecting God, and at the same time rejecting religion from their breasts and casting it behind their backs. Christians acknowledge One God; but in what manner is evident from their established [Athanasian] creed, which is as follows:The Catholic faith is this: That we worship One God in trinity, and trinity in unity. There are three Divine persons, Father, Son, and Holy Spirit, and yet there are not three Gods, but there is One God. There is one person of the Father, another of the Son, and another of the Holy Spirit, and their divinity is one, their glory equal, and their majesty coeternal. Thus the Father is God, the Son is God, and the Holy Spirit is God. But like as we are compelled by Christian verity to confess each person singly to be God and Lord, so we are forbidden by the Catholic religion to say there be three Gods or three Lords.Such is the Christian faith respecting the unity of God. But that the trinity of God and the unity of God in that creed are inconsistent with each other....
The other nations in the world possessing a religion and sound reason agree in acknowledging that God is One; all the Mohammedans in their empires; the Africans in many kingdoms of that continent; the Asiatics in their many kingdoms; and finally the Jews to this day. Of the most ancient people in the golden age, such as had any religion worshiped One God, whom they called Jehovah.
The same is true of the ancient people in the succeeding age, until monarchical governments were established, when worldly and afterwards corporeal loves began to close up the higher regions of the understanding, which previously had been open, and had been like temples and sacred recesses for the worship of One God.In order to reopen these and thus restore the worship of One God, the Lord God instituted a church among the posterity of Jacob, and made this the first of all the commandments of their religion:
Thou shalt have no other gods before Me (Exod. 20:3).Moreover, the name Jehovah, which He at this time restored, signifies the supreme and Only Being, the Source of everything that is or exists in the universe. Jove, a name derived possibly from Jehovah, was worshiped as a supreme god by the ancient heathen; and many other gods who composed his court they also clothed with divinity; while in the following age wise men, like Plato and Aristotle, confessed that these were not gods, but were so many properties, qualities, and attributes of the One God, being called gods because there was something Divine in each of them.
All sound reason, even when it is not religious, sees that every composite thing would of itself fall to pieces unless it depended upon some one thing; as in the case of man, composed of so many members, viscera, and organs of sensation and motion, unless they all depended on one soul; or the body itself, unless it depended on one heart. The same is true of a kingdom unless it depends on one king; a household, unless on one master; and every office, of which there are many kinds in every kingdom, unless on one officer. What would an army avail against the enemy unless it had a leader having supreme power, and officers subordinate to him, each of them having his proper command over the soldiers? So would it be with the church if it did not acknowledge One God, or with the angelic heaven, which is like a head to the church on earth, in both of which the Lord is the very soul. This is why heaven and the church are called His body; and when these do not acknowledge One God they are like a dead body, which being useless is carried away and buried.
(True Christian Religion 9, 10)