After Allah affirms in this noble Surah that `Isa was a worshipper and servant of Allah and He mentioned his birth from Maryam without a father, He then begins refuting those who claim that He has a son. Holy is He and far Exalted is He above such description. Allah says,
وَقَالُواْ اتَّخَذَ الرَّحْمَـنُ وَلَداً لَقَدْ جِئْتُمْ
(And they say: "The Most Gracious has begotten a son." Indeed you have brought forth) This means, "In this statement of yours."
شَيْئاً إِدّاً
(a thing Idda.) Ibn `Abbas, Mujahid, Qatadah and Malik all said, "Terrible." It has been said that it is pronounced Iddan, Addan, and Addan with elongation on the first vowel. All three of these pronunciations are known, but the most popular is the first. Allah said;
تَكَادُ السَّمَـوَتُ يَتَفَطَّرْنَ مِنْهُ وَتَنشَقُّ الاٌّرْضُ وَتَخِرُّ الْجِبَالُ هَدّاً - أَن دَعَوْا لِلرَّحْمَـنِ وَلَداً
(Whereby the heavens are almost torn, and the earth is split asunder, and the mountains Hadda, that they ascribe a son to the Most Gracious.) that is, out of their high esteem for Allah, when they hear this statement of wickedness coming from the Children of Adam. The reason for this is that these are creatures of Allah and they are established upon His Tawhid and the fact that there is no deity worthy of worship except Him. He has no partners, no peer, no child, no mate and no coequal. Rather, He is the One, Self-Sufficient Master, Whom all creatures are in need of. Ibn Jarir reported that Ibn `Abbas said concerning Allah's statement,
تَكَادُ السَّمَـوَتُ يَتَفَطَّرْنَ مِنْهُ وَتَنشَقُّ الاٌّرْضُ وَتَخِرُّ الْجِبَالُ هَدّاً - أَن دَعَوْا لِلرَّحْمَـنِ وَلَداً
(Whereby the heavens are almost torn, and the earth is split asunder, and the mountains Hadda, that they ascribe a son to the Most Gracious.) "Verily, the heavens, the earth, the mountains and all creatures -- except for humans and Jinns -- are frightened by the associating of partners with Allah. Creation will almost cease existing before the association of partners with Allah, due to His Greatness. Just as the idolator does not benefit by his good deeds because of associating partners with Allah, we hope that Allah would forgive the sins of those who believed in His absolute Oneness by worshipping Him alone. The Messenger of Allah ﷺ said,
«لَقِّنُوا مَوْتَاكُمْ شَهَادَةَ أَنْ لَا إِلَهَ إِلَّا اللهُ، فَمَنْ قَالَهَا عِنْدَ مَوْتِهِ وَجَبَتْ لَهُ الْجَنَّة»
(Encourage your dying people to testify to La ilaha illallah, for whoever says it at the time of their death, they will definitely enter into Paradise.) The people said, "O Messenger of Allah, what about he who says it while in good health" He replied,
«تِلْكَ أَوْجَبُ وَأَوْجَب»
(This will necessitate his entrance into Paradise even more.) Then he said,
«وَالَّذِي نَفْسِي بِيَدِهِ لَوْ جِيءَ بِالسَّموَاتِ وَالْأَرَضِينَ، وَمَا فِيهِنَّ وَمَا بَيْنَهُنَّ وَمَا تَحْتَهُنَّ، فَوُضِعْنَ فِي كِفَّةِ الْمِيزَانِ،وَوُضِعَتْ شَهَادَةُ أَنْ لَا إِلَهَ إِلَّا اللهُ فِي الْكِفَّةِ الْأُخْرى لَرَجَحَتْ بِهِن»
(I swear by He Whom my soul is in His Hand, if the heavens and the earths, and all that is in them, between them and under them, were brought and placed in a balance of a scale, and the testimony of La ilaha illallah was placed on the other side of the scale, the testimony would outweigh all of it.) This was recorded by Ibn Jarir and it is supported by the Hadith related to the story of the card. And Allah knows best. Ad-Dahhak said,
تَكَادُ السَّمَـوَتُ يَتَفَطَّرْنَ مِنْهُ
(Whereby the heavens are almost torn,) "This means to be split apart into pieces due to the fear of the magnificence of Allah." `Abdur-Rahman bin Zayd bin Aslam said,
وَتَنشَقُّ الاٌّرْضُ
(and the earth is split asunder,) "This is due to its anger on behalf of Allah, the Mighty and Sublime."
وَتَخِرُّ الْجِبَالُ هَدّاً
(and the mountains Hadda.) Ibn `Abbas said, "This means to be torn down." Sa`id bin Jubayr said, "Haddan means some of it is broken by other parts of it in succession." Imam Ahmad reported from Abu Musa that he said that the Messenger of Allah ﷺ said,
«لَا أَحَدَ أَصْبَرُ عَلَى أَذىً سَمِعَهُ مِنَ اللهِ إِنَّهُ يُشْرَكُ بِهِ وَيُجْعَلُ لَهُ وَلَدٌ، وَهُوَ يُعَافِيهِمْ وَيَدْفَعُ عَنْهُمْ وَيَرْزُقُهُم»
(There is no one more patient than Allah concerning something harmful that he hears. For verily, partners are associated with Him and a son is ascribed to Him, while He is the One Who gives them good health, protects them and sustains them.) This narration is also recorded in the Two Sahihs. In one wording of it he said,
«إِنَّهُمْ يَجْعَلُونَ لَهُ وَلَدًا وَهُوَ يَرْزُقُهُمْ وَيُعَافِيهِم»
(...that they attribute a son to Him, while He is the One Who sustains them and gives them good health.) Allah said;
وَمَا يَنبَغِى لِلرَّحْمَـنِ أَن يَتَّخِذَ وَلَداً
(But it is not suitable for the Most Gracious that He should beget a son.) Meaning that it is not befitting of Him, nor is it appropriate for His lofty majesty and greatness. There is no coequal for Him in His creation, because all creatures are His slaves. This is why He says,
إِن كُلُّ مَن فِى السَّمَـوَتِ وَالاٌّرْضِ إِلاَّ آتِى الرَّحْمَـنِ عَبْداً - لَّقَدْ أَحْصَـهُمْ وَعَدَّهُمْ عَدّاً
(There is none in the heavens and the earth but comes unto the Most Gracious as a slave. Verily, He knows each one of them, and has counted them a full counting.) He knows their number from the time He created them, until the Day of Resurrection, male and female, both the small and the large of them.
وَكُلُّهُمْ ءَاتِيهِ يَوْمَ الْقِيَـمَةِ فَرْداً
(And everyone of them will come to Him alone on the Day of Resurrection.) This means that there will be no helper for him and no one to save him, except Allah alone, Who has no partners. He judges His creatures as He wills and He is the Most Just, Who does not do even an atom's weight of injustice. He will not wrong anyone.