And if We had made it a non-Arabic Qur'an, they would have said, "Why are its verses not explained in detail [in our language]? Is it a foreign [recitation] and an Arab [messenger]?" Say, "It is, for those who believe, a guidance and cure." And those who do not believe - in their ears is deafness, and it is upon them blindness. Those are being called from a distant place.
Sahih International · EN
Si Nous en avions fait un Coran en une langue autre que l'arabe, ils auraient dit: «Pourquoi ses versets n'ont-ils pas été exposés clairement? quoi? Un [Coran] non-arabe et [un Messager] arabe?» Dis: «Pour ceux qui croient, il est une guidée et une guérison». Et quant à ceux qui ne croient pas, il y a une surdité dans leurs oreilles et ils sont frappés d'aveuglement en ce qui le concerne; ceux-là sont appelés d'un endroit lointain.
Muhammad Hamidullah · FR
Tafsir
Had I revealed this Qur’ān in a language other than that of the Arabs, the disbelievers among them would have said, “Why are its verses not made clear to us so that we can understand them?” Can the Qur’ān be in any language other than Arabic, while the one who brings it is an Arab? O Messenger! Say to these people: For those people who bring faith in Allah and believe in His messengers, the Qur’ān is a guidance from deviance and a cure for the ignorance and its consequences in the hearts. As for those who do not have faith in Allah, their ears are deaf and they are blinded from it so they do not understand it. These people are called from a distant place, so how could they hear the voice of the caller?
Al-Mukhtasar fi Tafsir al-Quran · Tafsir Center for Quranic StudiesRead Ibn Kathir (Ibn Kathir (abridged, English))
And if We had sent this as a Qur'an in a foreign language, they would have said: "Why are not its verses explained in detail? What! Not in Arabic nor an Arab?" Say: "It is for those who believe, a guide and a cure. And as for those who disbelieve, there is heaviness in their ears, and it is blindness for them. They are called from a place far away. (44)And indeed We gave Musa the Scripture, but dispute arose therein. And had it not been for a Word that went forth before from your Lord, and the matter would have been settled between them. But truly, they are in grave doubt thereto (45)
Rejection of the Qur'an is pure Stubbornness
Allah tells us that the Qur'an is so eloquent and perfect in its wording and meanings, yet despite that the idolators do not believe in it. He tells us that their disbelief is the disbelief of stubbornness, as He says elsewhere:
وَلَوْ نَزَّلْنَاهُ عَلَىٰ بَعْضِ الْأَعْجَمِينَ - فَقَرَأَهُ عَلَيْهِمْ مَا كَانُوا بِهِ مُؤْمِنِينَ
(And if We had revealed it unto any of the non-Arabs, and he had recited it unto them, they would not have believed in it.)(26:198-199). If the Qur'an had been revealed in the language of the non-Arabs, they would have said, because of their stubbornness:
لَوْلَا فُصِّلَتْ آيَاتُهُ ۖ أَأَعْجَمِيٌّ وَعَرَبِيٌّ ۗ
(Why are not its verses explained in detail? What! not in Arabic and an Arab?) meaning, why is it not revealed in detail in Arabic? And by way of denunciation they would have said, "What! not in Arabic nor from an Arab? – i.e., how can foreign words be revealed to an Arab who does not understand them? This interpretation was reported from Ibn 'Abbas, Mujahid, 'Ikrimah, Sa'id bin Jubayr, As-Suddi and others.
قُلْ هُوَ لِلَّذِينَ آمَنُوا هُدًى وَشِفَاءٌ ۖ
(Say: "It is for those who believe, a guide and a cure...") means, 'say, O Muhammad: this Qur'an, for the one who believes in it, is guidance for his heart and a cure for the doubts and confusion that exists in people's hearts.'
وَالَّذِينَ لَا يُؤْمِنُونَ فِي آذَانِهِمْ وَقْرٌ
(And as for those who disbelieve, there is heaviness in their ears,) means, they do not understand what is in it.
وَهُوَ عَلَيْهِمْ عَمًى
(and it is blindness for them.) means they are not guided to the explanations contained therein. This is like the Ayah:
وَنُنَزِّلُ مِنَ الْقُرْآنِ مَا هُوَ شِفَاءٌ وَرَحْمَةٌ لِلْمُؤْمِنِينَ ۙ وَلَا يَزِيدُ الظَّالِمِينَ إِلَّا خَسَارًا
(And We send down of the Qur'an that which is a healing and a mercy to those who believe, and it increases the wrongdoers nothing but loss.)(17:82).
أُولَٰئِكَ يُنَادَوْنَ مِنْ مَكَانٍ بَعِيدٍ
(They are called from a place far away.) Mujahid said, "Far away from their hearts." Ibn Jarir said, "It is as if the one who is addressing them is calling to them from a distant place, and they cannot understand what he is saying." This is like the Ayah:
وَمَثَلُ الَّذِينَ كَفَرُوا كَمَثَلِ الَّذِي يَنْعِقُ بِمَا لَا يَسْمَعُ إِلَّا دُعَاءً وَنِدَاءً ۚ صُمٌّ بُكْمٌ عُمْيٌ فَهُمْ لَا يَعْقِلُونَ
(And the example of those who disbelieve is as that of him who shouts to those (flock of sheep) that hears nothing but calls and cries. (They are) deaf, dumb and blind. So they do not understand.)(2:171)
Taking Musa as an Example
وَلَقَدْ آتَيْنَا مُوسَى الْكِتَابَ فَاخْتُلِفَ فِيهِ ۗ
(And indeed We gave Musa the Scripture, but dispute arose therein.) means, they disbelieved in him and did not show him any respect.
فَاصْبِرْ كَمَا صَبَرَ أُولُو الْعَزْمِ مِنَ الرُّسُلِ
(Therefore be patient as did the Messengers of strong will)(46:35).
وَلَوْلَا كَلِمَةٌ سَبَقَتْ مِن رَّبِّكَ إِلَىٰ أَجَلٍ مُّسَمًّى
(And had it not been for a Word that went forth before from your Lord for an appointed term,)(42:14) i.e., to delay the Reckoning until the Day of Resurrection,
لَقُضِيَ بَيْنَهُمْ
(the matter would have been settled between them.) means, the punishment would have been hastened for them. But they have an appointed time, beyond which they will find no escape.
وَإِنَّهُمْ لَفِي شَكٍّ مِنْهُ مُرِيبٍ
(But truly, they are in grave doubt thereto.) means, their words of disbelief are not due to any wisdom or insight on their part; rather they spoke without any attempt at examining it thoroughly. This was also the interpretation of Ibn Jarir, and it is a plausible interpretation. And Allah knows best.
Arabic text: Tanzil (Uthmani). Translations: Sahih International (en), Muhammad Hamidullah (fr). tanzil.net