Ante-Nicene Fathers, Vol I:
IRENÆUS: Chapter I.—There is but one God: the...

Chapter I.—There is but one God: the impossibility of its being otherwise.

1. It is proper, then, that I should begin with the first and most important head, that is, God the Creator, who made the heaven and the earth, and all things that are therein (whom these men blasphemously style the fruit of a defect), and to demonstrate that there is nothing either above Him or after Him; nor that, influenced by any one, but of His own free will, He created all things, since He is the only God, the only Lord, the only Creator, the only Father, alone containing all things, and Himself commanding all things into existence.

2. For how can there be any other Fulness, or Principle, or Power, or God, above Him, since it is matter of necessity that God, the Pleroma (Fulness) of all these, should contain all things in His immensity, and should be contained by no one? But if there is anything beyond Him, He is not then the Pleroma of all, nor does He contain all. For that which they declare to be beyond Him will be wanting to the Pleroma, or, [in other words,] to that God who is above all things. But that which is wanting, and falls in any way short, is not the p. 360 Pleroma of all things. In such a case, He would have both beginning, middle, and end, with respect to those who are beyond Him. And if He has an end in regard to those things which are below, He has also a beginning with respect to those things which are above. In like manner, there is an absolute necessity that He should experience the very same thing at all other points, and should be held in, bounded, and enclosed by those existences that are outside of Him. For that being who is the end downwards, necessarily circumscribes and surrounds him who finds his end in it. And thus, according to them, the Father of all (that is, He whom they call Proön and Proarche), with their Pleroma, and the good God of Marcion, is established and enclosed in some other, and is surrounded from without by another mighty Being, who must of necessity be greater, inasmuch as that which contains is greater than that which is contained. But then that which is greater is also stronger, and in a greater degree Lord; and that which is greater, and stronger, and in a greater degree Lord—must be God.

3. Now, since there exists, according to them, also something else which they declare to be outside of the Pleroma, into which they further hold there descended that higher power who went astray, it is in every way necessary that the Pleroma either contains that which is beyond, yet is contained (for otherwise, it will not be beyond the Pleroma; for if there is anything beyond the Pleroma, there will be a Pleroma within this very Pleroma which they declare to be outside of the Pleroma, and the Pleroma will be contained by that which is beyond: and with the Pleroma is understood also the first God); or, again, they must be an infinite distance separated from each other —the Pleroma [I mean], and that which is beyond it. But if they maintain this, there will then be a third kind of existence, which separates by immensity the Pleroma and that which is beyond it. This third kind of existence will therefore bound and contain both the others, and will be greater both than the Pleroma, and than that which is beyond it, inasmuch as it contains both in its bosom. In this way, talk might go on for ever concerning those things which are contained, and those which contain. For if this third existence has its beginning above, and its end beneath, there is an absolute necessity that it be also bounded on the sides, either beginning or ceasing at certain other points, [where new existences begin.] These, again, and others which are above and below, will have their beginnings at certain other points, and so on ad infinitum; so that their thoughts would never rest in one God, but, in consequence of seeking after more than exists, would wander away to that which has no existence, and depart from the true God.

4. These remarks are, in like manner, applicable against the followers of Marcion. For his two gods will also be contained and circumscribed by an immense interval which separates them from one another. But then there is a necessity to suppose a multitude of gods separated by an immense distance from each other on every side, beginning with one another, and ending in one another. Thus, by that very process of reasoning on which they depend for teaching that there is a certain Pleroma or God above the Creator of heaven and earth, any one who chooses to employ it may maintain that there is another Pleroma above the Pleroma, above that again another, and above Bythus another ocean of Deity, while in like manner the same successions hold with respect to the sides; and thus, their doctrine flowing out into immensity, there will always be a necessity to conceive of other Pleroma, and other Bythi, so as never at any time to stop, but always to continue seeking for others besides those already mentioned. Moreover, it will be uncertain whether these which we conceive of are below, or are, in fact, themselves the things which are above; and, in like manner, [it will be doubtful] respecting those things which are said by them to be above, whether they are really above or below; and thus our opinions will have no fixed conclusion or certainty, but will of necessity wander forth after worlds without limits, and gods that cannot be numbered.

5. These things, then, being so, each deity will be contented with his own possessions, and will not be moved with any curiosity respecting the affairs of others; otherwise he would be unjust, and rapacious, and would cease to be what God is. Each creation, too, will glorify its own maker, and will be contented with him, not knowing any other; otherwise it would most justly be deemed an apostate by all the others, and would receive a richly-deserved punishment. For it must be either that there is one Being who contains all things, and formed in His own territory all those things which have been created, according to His own will; or, again, that there are numerous unlimited creators and gods, who begin from each other, and end in each other on every side; and it will then be necessary to allow that all the rest are contained from without by some one who is greater, and that they are each of them shut up within their own territory, and remain in it. No one of them all, therefore, is God. For there will be [much] wanting to every one of them, possessing [as he will do] only a very small part when compared with all the rest. The name of the Omnipotent will thus be brought to an end, and such an opinion will of necessity fall to impiety.