At the time the Sahidic Coptic translation was being produced, leaders in the church were combating a brand of "Christian" Gnosticism called Marcionism. Marcion (died about 154 CE) was excommunicated from the church in Rome in 144, after which he formed his own church. His teachings became widely disseminated all over the Roman empire by the year 150
Among other things that conflicted with orthodox belief, Marcion taught the Gnostic idea that the Creator God of the "Old Testament" was a separate, inferior God to the God of the "New Testament," and that this inferior God was the one responsible for all the evils of the world.
Irenaeus and other leaders of the church fiercely combated this view of two Gods, so much so that Irenaeus did not accept that the "God of this world" mentioned at 2 Corinthians 4:4 could be other than God himself. In Against Heresies book 3, chapter 7, he writes: "The true sense...is contained in the expression, "God hath blinded the minds of the unbelievers of this world."....For Paul does not say, "the God of this world," as if recognising any other beyond Him; but he confessed God as indeed God. And he says, "the unbelievers of this world," because they shall not inherit the future age of incorruption. I shall show from Paul himself, how it is that God has blinded the minds of those that believe not."
This effort to combat Gnostic Marcionism and "the intolerable absurdities of Gnosticism" (ANF, volume 1, page 310) appears to be behind the rendering of 2 Corinthians 4:4 that is found in some texts of the ancient Syriac Peshitta and Sahidic Coptic versions. The Peshitta according to George Lamsa’s Holy Bible from the Ancient Eastern Text: "To those in this world whose minds have been blinded by God, because they did not believe, lest the light of the glorious gospel of Christ, who is the likeness of God, should shine on them." (Emphasis added)
The Sahidic Coptic text of 2 Corinthians 4:4 says: "Therefore, God has closed the minds of the unbelievers of this world , so that they might not see the light of the glorious Good News of the Christ, who is the image of God." (Emphasis added)
It is not known if there is any Greek text that reads this way. Most versions of 2 Corinthians 4:4 appear to be based on a Greek text that says: "the god of this world has blinded the minds of the unbelievers."
However, 14th century English translation made by John Wycliffe, based on the Old Latin version reads similarly, linking "of this world" with the unbelievers or "unfaithful men," and linking God with the blinding or closing of their minds or "souls": "In whiche god hath blende the soulis of vnfeithful men of this world, that the liztnynge of the gospel of the glorie of crist, whiche is the ymage of god schyne not." In more modern English, Wycliffe’s translation says: "In which God has blinded the souls of unfaithful men of this world, that the lightings of the gospel of the glory of Christ, which is the image of God, shine not." For a scan of Wycliffe's original in Old English, see:
It appears that the Coptic translators wished to clarify the truth of a verse of Scripture that was currently being misinterpreted by Gnostics. Perhaps like Irenaeus, they believed that in so doing, they had the support of other verses in the Bible. For example, 2 Thessalonians 2:11 indicated that God "allowed" spiritual blindness to occur on the part of unbelievers. John 12:39, 40 stated that God had "hardened" the hearts and "pasted together" the ears of others who rejected truth.
The Coptic translators obviously rejected the Gnostic Marcionite interpretation that some God other than the true God was responsible for creating and ruling the world, that this God in turn was evil, and the Coptic translators apparently translated 2 Corinthians 4:4 with this anti-heretical purpose in mind.
We may appreciate now that Satan is the "god of this world" only God’s allowance until he is defeated decisively by the victorious Jesus Christ. But the Coptic translators were reacting to a widespread heresy of their times, to which they did not wish to give any inadvertent aid, or any interpretation to twist. At the same time, this particular translational curiosity is helpful in positively dating the Sahidic Coptic version to the 2nd or 3rd centuries CE.
Likewise today, translators often make decisions on the basis of what they perceive to be not only the grammar of a text, but also the intent and purpose of the text. In modern critical texts, translators have sometimes rearranged (emended) whole sentences according to their best estimate of what the text was or should be saying. In such cases, judgment calls are made, the validity of which can sometimes be assessed only by the passing of time.
"If you remain in my word, you are truly my disciples. You will know the truth, and the truth will make you free." –- Coptic John 8:31, 32