Indeed earlier in the same book Irenaeus seems to attack the heretics for positing the existence of a second god who 'contains heaven and earth' while still positing a higher unknown Father above him. This is how the Second Book starts:
In the present book, I shall establish those points which fit in with my design, so far as time permits, and overthrow, by means of lengthened treatment under distinct heads, their whole system; for which reason, since it is an exposure and subversion of their opinions, I have so entitled the composition of this work. For it is fitting, by a plain revelation and overthrow of their conjunctions, to put an end to these hidden alliances, and to Bythus himself, and thus to obtain a demonstration that he never existed at any previous time, nor now has any existence.
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.
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 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 Proon 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.
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 , 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.
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, 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.
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.
Those, moreover, who say that the world was formed by angels, or by any other maker of it, contrary to the will of Him who is the Supreme Father, err first of all in this very point, that they maintain that angels formed such and so mighty a creation, contrary to the will of the Most High God. This would imply that angels were more powerful than God; or if not so, that He was either careless, or inferior, or paid no regard to those things which took place among His own possessions, whether they turned out ill or well, so that He might drive away and prevent the one, while He praised and rejoiced over the other. But if one would not ascribe such conduct even to a man of any ability, how much less to God
2. Next let them tell us whether these things have been formed within the limits which are contained by Him, and in His proper territory, or in regions belonging to others, and lying beyond Him? But if they say [that these things were done] beyond Him, then all the absurdities already mentioned will face them, and the Supreme God will be enclosed by that which is beyond Him, in which also it will be necessary that He should find His end. If, on the other hand, [these things were done] within His own proper territory, it will be very idle to say that the world was thus formed within His proper territory against His will by angels who are themselves under His power, or by any other being, as if either He Himself did not behold all things which take place among His own possessions, or(2) was not aware of the things to be done by angels.
3. If, however, [the things referred to were done] not against His will, but with His concurrence and knowledge, as some [of these men] think, the angels, or the Former of the world [whoever that may have been], will no longer be the causes of that formation, but the will of God. For if He is the Former of the world, He too made the angels, or at least was the cause of their creation; and He will be regarded as having made the world who prepared the causes of its formation. Although they maintain that the angels were made by a long succession downwards, or that the Former of the world [sprang] from the Supreme Father, as Basilides asserts; nevertheless that which is the cause of those things which have been made will still be traced to Him who was the Author of such a succession. [The case stands] just as regards success in war, which is ascribed to the king who prepared those things which are the cause of victory; and, in like manner, the creation of any state, or of any work, is referred to him who prepared materials for the accomplishment of those results which were afterwards brought about. Wherefore, we do not say that it was the axe which cut the wood, or the saw which divided it; but one would very properly say that the man cut and divided it who formed the axe and the saw for this purpose, and [who also formed] at a much earlier date all the tools by which the axe and the saw themselves were formed. With justice, therefore, according to an analogous process of reasoning, the Father of all will be declared the Former of this world, and not the angels, nor any other [so-called] former of the world, other than He who was its Author, and had formerly(3) been the cause of the preparation for a creation of this kind.
4. This manner of speech may perhaps be plausible or persuasive to those who know not God, and who liken Him to needy human beings, and to those who cannot immediately and without assistance form anything, but require many instrumentalities to produce what they intend. But it will not be regarded as at all probable by those who know that God stands in need of nothing, and that He created and made all things by His Word, while He neither required angels to assist Him in the production of those things which are made, nor of any power greatly inferior to Himself, and ignorant of the Father, nor of any defect or ignorance, in order that he who should know Him might become man.(4) But He Himself in Himself, after a fashion which we can neither describe nor conceive, predestinating all things, formed them as He pleased, bestowing harmony on all things, and assigning them their own place, and the beginning of their creation. In this way He conferred on spiritual things a spiritual and invisible nature, on super-celestial things a celestial, on angels an angelical, on animals an animal, on beings that swim a nature suited to the water, and on those that live on the land one fitted for the land--on all, in short, a nature suitable to the character of the life assigned them--while He formed all things that were made by His Word that never wearies.
5. For this is a peculiarity of the pre-eminence of God, not to stand in need of other instruments for the creation of those things which are summoned into existence. His own Word is both suitable and sufficient for the formation of all things, even as John, the disciple of the Lord, declares regarding Him: "All things were made by Him, and without Him was nothing made."(1) Now, among the "all things" our world must be embraced. It too, therefore, was made by His Word, as Scripture tells us in the book of Genesis that He made all things connected with our world by His Word. David also expresses the same truth [when he says] "For He spake, and they were made; He commanded, and they were created."(2) Whom, therefore, shall we believe as to the creation of the world--these heretics who have been mentioned that prate so foolishly and inconsistently on the subject, or the disciples of the Lord, and Moses, who was both a faithful servant of God and a prophet? He at first narrated the formation of the world in these words: "In the beginning God created the heaven and the earth,"(3) and all other things in succession; but neither gods nor angels [had any share in the work].
Now, that this God is the Father of our Lord Jesus Christ, Paul the apostle also has declared, [saying,] "There is one God, the Father, who is above all, and through all things, and in us all."(4) I have indeed proved already that there is only one God; but I shall further demonstrate this from the apostles themselves, and from the discourses of the Lord. For what sort of conduct would it be, were we to forsake the utterances of the prophets, of the Lord, and of the apostles, that we might give heed to these persons, who speak not a word of sense?
The Bythus, therefore, whom they conceive of with his Pleroma, and the God of Marcion, are inconsistent. If indeed, as they affirm, he has something subjacent and beyond himself, which they style vacuity and shadow, this vacuum is then proved to be greater than their Pleroma. But it is inconsistent even to make this statement, that while he contains all things within himself, the creation was formed by some other. For it is absolutely necessary that they acknowledge a certain void and chaotic kind of existence (below the spiritual Pleroma) in which this universe was formed, and that the Propator purposely left this chaos as it was, either(5) knowing beforehand what things were to happen in it, or being ignorant of them. If he was really ignorant, then God will not be prescient of all things. But they will not even [in that case] be able to assign a reason on what account He thus left this place void during so long a period of time. If, again, He is prescient, and contemplated mentally that creation which was about to have a being in that place, then He Himself created it who also formed it beforehand [ideally] in Himself.