339. Men ought to believe, that is, have faith, in God the Savior Jesus Christ, because that is a faith in a visible God within whom is the invisible; and faith in a visible God, who is at once Man and God, enters into a man; for faith in its essence is spiritual but in its form is natural; consequently with man such a faith becomes spiritual-natural. For anything spiritual, in order to be anything with man, must have a recipient in the natural. The naked spiritual does indeed enter into man, but it is not received; it is like the ether, which flows in and out producing no effect, for to produce an effect there must be perception and consequent reception, both of these in his mind; and no such reception is possible with man except in his natural. But on the other hand merely natural faith, or faith destitute of a spiritual essence, is not faith, but only persuasion or knowledge. In externals persuasion emulates faith; but since there is in its internals no spirituality, neither is there anything saving in it. Such is the faith of all who deny the Divinity of the Lord's Human; such was the Arian faith, and such also is the Socinian faith, because both reject the Lord's Divinity. What is faith without an object toward which it is determined? Is it not like gazing into the universe, where the sight falls, as it were, into vacuity and is lost? It is like a bird flying beyond the atmosphere into the ether, where, as in a vacuum, it ceases to breathe. The abiding of this faith in man's mind may be compared to that of the winds in the wings [halls?] of Aeolus, or of light in a falling star. It rises like a comet with a long tail, and like it passes over and disappears. [2] In a word, faith in an invisible God is actually blind, since the human mind fails to see its God; and the light of that faith, not being a spiritual-natural faith, is a fatuous light; which light is like that of the glow-worm, or like that seen above marshes or sulphurous glebes at night, or like the phosphorescence of rotten wood. From that light nothing comes except what pertains to fantasy, which creates a belief that the apparent is the real, when yet it is not. Faith in an invisible God shines with no other light than this, especially when God is thought to be a Spirit, and spirit is thought to be like ether. What follows but that man regards God as he does the ether? Consequently he seeks God in the universe; and when he does not find Him there, he believes the nature of the universe to be God. This is the origin of the prevailing naturalism of the day. Did not the Lord say, That no one ever heard the Father's voice or saw His shape? (John 5:37);