Commodian was a third century Christian Latin poet of either North African or Syrian origin, who we know primarily through the only part of his corpus that has been passed down to us: 'Instructiones'. While the text of another poem 'Carmen Apologeticum' is generally credited to have been authored by Commodian: I have taken the liberty of excluding it from my comments here, because the only evidence we have to do so is that the style is generally similar (thus there is little definite evidence to ascribe it to Commodian in my view).
Commodian; as you might expect, brings up the subject of the jews in his 'Instructiones' several times over the course of the eighty individual poems that make up the text. In the poem 'The Fanatics Who Judaise' we read as follows:
'What! Are thou half a Jew? Will thou be half profane? Whence thou shalt not when dead escape the judgment of Christ. Thou thyself blindly wanders, and foolishly goes in among the blind. And thus the blind lead the blind into the ditch. Thou goes where thou knows not, and hence ignorantly withdraws. Let them who are learning go to the learned, and let the learned depart. But thou goes to those from whom thou can learn nothing. Thou goes forward before the doors, and hence also thou goes to the idols. Ask first of all what is commanded in the law. Let them tell you if it be commanded to adore the gods; for they are ignored in respect of that which they are especially able to do. But because they are guilty of that very crime, they relate nothing concerning the commandments of God save what is marvellous. Then, however, they blindly lead you with them into the ditch. There are deaths too well known by them to relate, or because the heaping up of the plough closes up the field. The Almighty would not have them understand their King. Why such a wickedness? He Himself took refuge from those bloody men. He gave Himself to us by a superadded law. Hence now they lie concealed with us, deserted by their King. But if you think that in them there is hope, you are altogether in error if you worship God and heathen temples.' (1)
In this passage Commodian is attacking the age-old Christian heresy of Judaising or in other words Christians becoming jews or following theological positions/using rituals are that were in Commodian's mind closely associated with jews and Judaism. He argues that Judaism is a religion of the unlearned and the ignorant as well as those who follow the dictates of the law (i.e. the Torah) so closely that if the Torah was argued by a jew to require the worship of pagan gods/idols: then Judaisers would perform this manifest heresy due to their ignorance and lack of learning.
This ignorance and lack of learning is exemplified for Commodian in the fact that Judaisers only believe what is miraculous/spectacular/wondrous and do not apply any sort of rational critique to their religious beliefs, which is personified in the theology of the Judaisers which Commodian argues lacks any Biblical support and to affirm its case it relies on selective excerpts which is misrepresents by removing them from their scriptural context (thus it is a case of the jews and their dupes deluding the mass of the Judaisers who are proverbial ignorant and illiterate peasants).
This theme of the fundamental credulity and superstitious nature of the Judaisers is also seen when Commodian turns his attention to the jews. Since as he writes in the poem titled 'To the Jews':
'Evil always, and recalcitrant, with a stiff neck you wish not that you should be overcome; thus you will be heirs for Isaiah said that you were of hardened heart. You look upon the law which Moses in wrath dashed to pieces; and the same Lord gave to him a second law. In that he placed his hope; but you, half healed, reject it, and therefore you shall not be worthy of the kingdom of heaven.' (2)
We can see in the above that Commodian is focusing on the blindness of the jews to the gospel of Christ and trying to convert them to its message (i.e. the jews like the Judaisers are adverse to reason and simply rely on superstitions and sophistry to support their beliefs). He tries to achieve this by warning the jews that if they don't convert to Christianity soon then the last judgement will come and then they will all be confined to the tortures of hell for all eternity. This descent into hell Commodian styles in the light of the punishments visited on Israel in the Tanakh and specifically the book of Isaiah (with a slight reference to the book of Exodus) in order to make it as relevant and appealing as possible to the jews.
Essentially Commodian is appealing to the jews in the language of Judaism to convert now or suffer eternally in hell for not recognizing the Messiah for what he was/is. We can particularly see this kind of 'Christianity is the new Judaism' language come out when Commodian writes in his poem 'Also to the Jews' that:
'Look upon Leah, that was a type of the synagogue, which Jacob received as a sign, with eyes so weak; and yet he served again for the younger one beloved: a true mystery, and a type of our Church. Consider what was abundantly said of Rebecca from heaven; whence, imitating the alien, you may believe in Christ. Hence come to Tamar and the offspring of twins. Look to Cain, the first tiller of the earth, and Abel the shepherd, who was an unspotted offerer in the ruin of his brother, and was slain by his brother. Thus therefore perceive, that the younger are approved by Christ.' (3)
We should note the multiple uses of Tanakh (i.e. the Old Testament) references in this passage which are intended to closely associate the new religion of Christianity to Judaism by arguing that Jesus was the long-awaited Messiah according to the Torah.
Further Commodian seeks to draw direct parallels between the synagogue and the Church and points out that while Christianity is a primarily (as it was at this point) a religion of the gentiles: the jews should imitate Rebecca and prove their suitability of being received into the (new) family of Abraham by seeking to drink from the gospel of Jesus Christ.
In other words Commodian here is arguing that Christianity is a form of Judaism and that as such jews should be part of Christianity's fold not excluded from this. This is clearly demonstrated when he describes how he believes shall react at the second coming of Christ:
'The Jews, recapitulating Scriptures from him, exclaim at the same time to the Highest that they have been deceived.' (4)
In other words: the jews have been blind and not been willing to listen to the message of reconciliation with Yahweh that Jesus brings them, but rather have been 'hard of heart' and their followers (the Judaisers) have been ignorant simpletons who have been conned by the jews into error (whether or not they are the devil's own foot-soldiers is not stated although presumably what Commodian himself believed).
However unless both groups convert to (true) Christianity then; according to Commodian, they are going to burn in the fires of hell (along with the pagans and any other individuals or groups regarded as heretics by Commodian's sect): it is as simple as that for him.
References
(1) Commodian Inst. 37
(2) Ibid. 38
(3) Ibid. 39
(4) Ibid. 41