Allah tells us that the revelation of this Book, which is the magnificent Qur'an, is from Him, and is truth in which there is no doubt whatsoever. This is like the Ayat:
﴿وَإِنَّهُ لَتَنزِيلُ رَبِّ الْعَـلَمِينَ - نَزَلَ بِهِ الرُّوحُ الاٌّمِينُ - عَلَى قَلْبِكَ لِتَكُونَ مِنَ الْمُنْذِرِينَ - بِلِسَانٍ عَرَبِىٍّ مُّبِينٍ ﴾
(And truly, this is a revelation from the Lord of the creatures, which the trustworthy Ruh (Jibril) has brought down upon your heart that you may be (one) of the warners, in the plain Arabic language.) (26:192-195)
﴿إِنَّ الَّذِينَ كَفَرُواْ بِالذِّكْرِ لَمَّا جَآءَهُمْ وَإِنَّهُ لَكِتَـبٌ عَزِيزٌ - لاَّ يَأْتِيهِ الْبَـطِلُ مِن بَيْنِ يَدَيْهِ وَلاَ مِنْ خَلْفِهِ تَنزِيلٌ مِّنْ حَكِيمٍ حَمِيدٍ ﴾
(And verily, it is a mighty Book. Falsehood cannot come to it from before it or behind it, (it is) sent down by the All-Wise, Worthy of all praise.) (40: 41,42) And Allah says here:
﴿تَنزِيلُ الْكِتَـبِ مِنَ اللَّهِ الْعَزِيزِ﴾
(The revelation of this Book is from Allah, the Almighty,) meaning, the Almighty, All-Powerful.
﴿الْحَكِيمُ﴾
(the All-Wise.) meaning, in all that He says, does, legislates and decrees.
﴿إِنَّآ أَنزَلْنَآ إِلَيْكَ الْكِتَـبَ بِالْحَقِّ فَاعْبُدِ اللَّهَ مُخْلِصاً لَّهُ الدِّينِ ﴾
(Verily, We have sent down the Book to you in truth. So, worship Allah by doing religious deeds sincerely for Him only.) means, so worship Allah Alone with no partner or associate, and call mankind to that, and teach them that it is not right to worship anyone or anything except Him Alone, and He has no partner, equal or rival. Allah says:
﴿أَلاَ لِلَّهِ الدِّينُ الْخَالِصُ﴾
(Surely, the religion is for Allah only.) meaning, He will not accept any deed unless it is done purely and sincerely for Him Alone, with no partner or associate. Then Allah tells us that the idolators say:
﴿مَا نَعْبُدُهُمْ إِلاَّ لِيُقَرِّبُونَآ إِلَى اللَّهِ زُلْفَى﴾
(We worship them only that they may bring us near to Allah.) meaning what motivates them to worship them is the fact that they made their idols in the image of the angels -- or so they claim -- and when they worship those images it is like worshipping the angels, so that they will intercede with Allah for them to help and give them provision and other worldly needs. As far as the resurrection is concerned, they denied it and did not believe in it. Qatadah, As-Suddi and Malik said, narrating from Zayd bin Aslam and Ibn Zayd:
﴿إِلاَّ لِيُقَرِّبُونَآ إِلَى اللَّهِ زُلْفَى﴾
(only that they may bring us near to Allah. ) means, "So that they may intercede for us and bring us closer to Him.'' During Jahiliyyah, they used to recite the following for their Talbiyah when they performed Hajj; "At Your service, You have no partner except the partner You have; he and all that he owns belong to You.'' This pretentious argument which the idolators of all times, ancient and modern, used as evidence is what the Messengers, may the blessings and peace of Allah be upon them all, came to refute and forbid, and to call people to worship Allah Alone with no partner or associate. This is something that the idolators themselves invented; Allah did not give them permission for it, nor does He approve of it; indeed, He hates it and forbids it.
﴿وَلَقَدْ بَعَثْنَا فِى كُلِّ أُمَّةٍ رَّسُولاً أَنِ اعْبُدُواْ اللَّهَ وَاجْتَنِبُواْ الْطَّـغُوتَ﴾
(And verily, We have sent among every Ummah a Messenger (proclaiming): "Worship Allah, and avoid Taghut.'') (16:36)
﴿وَمَآ أَرْسَلْنَا مِن قَبْلِكَ مِن رَّسُولٍ إِلاَّ نُوحِى إِلَيْهِ أَنَّهُ لا إِلَـهَ إِلاَّ أَنَاْ فَاعْبُدُونِ ﴾
(And We did not send any Messenger before you but We revealed to him (saying): "None has the right to be worshipped but I (Allah), so worship Me.'') (21:25) And Allah tells us that the angels in the heavens, those who are close to Him and others, are all servants who submit humbly to Allah. They do not intercede with Him except by His leave for the one with whom He is pleased. They are not like the princes and ministers of their (the idolators') kings who intercede with them without their permission for both those whom the kings like and those whom they hate.
﴿فَلاَ تَضْرِبُواْ لِلَّهِ الاٌّمْثَالَ﴾
(So put not forward similitudes for Allah) (16:74). Exalted be Allah far above that.
﴿إِنَّ اللَّهَ يَحْكُمُ بَيْنَهُمْ﴾
(Verily, Allah will judge between them) means, on the Day of Resurrection,
﴿فِى مَا هُمْ فِيهِ يَخْتَلِفُونَ﴾
(concerning that wherein they differ.) means, He will judge between His creation on the Day of Resurrection and will reward or punish each person according to his deeds.
﴿وَيَوْمَ يَحْشُرُهُمْ جَمِيعاً ثُمَّ يَقُولُ لِلْمَلَـئِكَةِ أَهَـؤُلاَءِ إِيَّاكُمْ كَانُواْ يَعْبُدُونَ - قَالُواْ سُبْحَـنَكَ أَنتَ وَلِيُّنَا مِن دُونِهِمْ بَلْ كَانُواْ يَعْبُدُونَ الْجِنَّ أَكْـثَرُهُم بِهِم مُّؤْمِنُونَ ﴾
(And (remember) the Day when He will gather them all together, then He will say to the angels: "Was it you that these people used to worship'' They (the angels) will say: "Glorified be You! You are our Wali (Lord) instead of them. Nay, but they used to worship the Jinn; most of them were believers in them.'') (34:40-41)
﴿إِنَّ اللَّهَ لاَ يَهْدِى مَنْ هُوَ كَـذِبٌ كَـفَّارٌ﴾
(Truly, Allah guides not him who is a liar, and a disbeliever.) means, He will not show true guidance to one who deliberately tells lies about Allah and whose heart rejects the signs and proof of Allah. Then Allah states that He does not have any offspring, as the ignorant idolators claim the angels to be, and as the stubborn Jews and Christians claim `Uzayr and `Isa to be. Allah, may He be blessed and exalted, says:
﴿لَّوْ أَرَادَ اللَّهُ أَن يَتَّخِذَ وَلَداً لاَّصْطَفَى مِمَّا يَخْلُقُ مَا يَشَآءُ﴾
(Had Allah willed to take a son (or offspring), He could have chosen whom He willed out of those whom He created.) meaning, the matter would not have been as they claim. This is a conditional sentence which does not imply that this happened or that it is permitted; indeed, it is impossible. The aim is only to point out the ignorance of their claims. It is like the Ayat:
﴿لَوْ أَرَدْنَآ أَن نَّتَّخِذَ لَهْواً لاَّتَّخَذْنَـهُ مِن لَّدُنَّآ إِن كُنَّا فَـعِلِينَ ﴾
(Had We intended to take a pastime, We could surely have taken it from Us, if We were going to do (that).) (21:17)
﴿قُلْ إِن كَانَ لِلرَّحْمَـنِ وَلَدٌ فَأَنَاْ أَوَّلُ الْعَـبِدِينَ ﴾
(Say: "If the Most Gracious had a son, then I am the first of worshippers.'') (43:81) All of these Ayat are conditional, and it is permissible to form a conditional sentence referring to something that is impossible if it serves the purposes of the speaker.
﴿سُبْحَـنَهُ هُوَ اللَّهُ الْوَحِدُ الْقَهَّارُ﴾
(But glory be to Him! He is Allah, the One, the Irresistible.) means, exalted and sanctified be He above the idea that He could have any offspring, for He is the One, the Only, the Unique, the Self-Sufficient Master to Whom everything is enslaved and is in need of. He is the One Who is independent of all else, Who has subjugated all things and they submit humbly to Him. Blessed and exalted be He far above what the wrongdoers and deniers say.
﴿خَلَقَ السَّمَـوَتِ وَالاٌّرْضَ بِالْحَقِّ يُكَوِّرُ الَّيْـلَ عَلَى النَّهَـارِ وَيُكَوِّرُ النَّـهَارَ عَلَى الَّيْلِ وَسَخَّـرَ الشَّمْسَ وَالْقَمَرَ كُـلٌّ يَجْرِى لاًّجَـلٍ مُّسَـمًّى أَلا هُوَ الْعَزِيزُ الْغَفَّارُ - خَلَقَكُمْ مِّن نَّفْسٍ وَحِدَةٍ ثُمَّ جَعَلَ مِنْهَا زَوْجَهَا وَأَنزَلَ لَكُمْ مِّنَ الاٌّنْعَـمِ ثَمَـنِيَةَ أَزْوَجٍ يَخْلُقُكُمْ فِى بُطُونِ أُمَّهَـتِكُـمْ خَلْقاً مِّن بَعْدِ خَلْقٍ فِى ظُلُمَـتٍ ثَلَـثٍ ذَلِكُمُ اللَّهُ رَبُّكُمْ لَهُ الْمُلْكُ لا إِلَـهَ إِلاَّ هُوَ فَأَنَّى تُصْرَفُونَ ﴾
(5. He has created the heavens and the earth with truth. He makes the night to go in the day and makes the day to go in the night. And He has subjected the sun and the moon. Each running for an appointed term. Verily, He is the Almighty, the Oft-Forgiving.) (6. He created you (all) from a single person; then made from him his wife. And He has sent down for you of An`am eight pairs. He creates you in the wombs of your mothers, creation after creation in three veils of darkness. Such is Allah your Lord. His is the kingdom. La ilaha illa Huwa. How then are you turned away)