Allah tells us how ignorant the idolators are; instead of worshipping Allah, they worship idols which do not possess the power either to harm or benefit. They do this with no evidence or proof; the only thing that led them to do this was their own whims and desires. So they take these idols as protectors and fight for their sake, and they oppose Allah and His Messenger and the believers for their sake. Similarly Allah says:
وَكَانَ الْكَـفِرُ عَلَى رَبِّهِ ظَهِيراً
(and the disbeliever is ever a helper against his Lord.) meaning, he is a supporter of Shaytan against the party of Allah, but the party of Allah are the ones who will prevail, as Allah says:
(And they have taken besides Allah gods, hoping that they might be helped. They cannot help them, but they will be brought forward as a troop against those who worshipped them.) (36:74-75) meaning, the gods which they worshipped instead of Allah cannot help them. These ignorant people are troops for the idols and are ready to fight for their sake and protect their sanctuaries, but in the end the victory will be for Allah and His Messenger and the believers, in this world and the Hereafter.
وَكَانَ الْكَـفِرُ عَلَى رَبِّهِ ظَهِيراً
(and the disbeliever is ever a helper against his Lord. ) Mujahid said: "He supports and helps the Shaytan in disobedience towards Allah.
The Messenger brings Glad Tidings and Warnings
Then Allah tells His Messenger:
وَمَآ أَرْسَلْنَـكَ إِلاَّ مُبَشِّراً وَنَذِيراً
(And We have sent you only as a bearer of good news and a warner.) meaning, a bringer of good news to the believers, a warner to the disbelievers; bringing good news of Paradise to those who obey Allah, and bringing warnings of a dreadful punishment for those who go against the commandments of Allah.
قُلْ مَآ أَسْأَلُكُمْ عَلَيْهِ مِنْ أَجْرٍ
(Say: "No reward do I ask of you for this...'') `for conveying this message and this warning, I do not ask for any reward from your wealth; I am only doing this for the sake of Allah, may He be exalted.'
لِمَن شَآءَ مِنكُمْ أَن يَسْتَقِيمَ
(To whomsoever among you who wills to walk straight) (81:28).
(is the First and the Last, the Most High and the Most Near. And He is the All-Knower of everything) (57:3). The Eternal, Ever-Lasting, Ever-Living, Self-Sufficient One, the Lord and Sovereign of all things, the One to Whom you should always turn. Allah is the One in Whom you should put your trust and to Whom you should turn for refuge, He will be sufficient for you and will be your helper and supporter, and will cause you to prevail. As Allah says:
(Say: "He is the Most Gracious, in Him we believe, and in Him we put our trust.'') (67:29)
وَكَفَى بِهِ بِذُنُوبِ عِبَادِهِ خَبِيراً
(and sufficient is He as the All-Knower of the sins of His servants) means, by His perfect knowledge nothing is hidden from Him nor can anything be hidden from Him, not even a speck of dust's weight.
الَّذِى خَلَقَ السَّمَـوَتِ وَالاٌّرْضَ
(Who created the heavens and the earth...) means, He is the Ever-Living Who never dies, He is the Creator, Sustainer and Sovereign of all things, Who by His might and power created the seven heavens with their vast height and width, and the seven earths with their great depths and density.
(Then He rose over (Istawa) the Throne. The Most Gracious! Ask Him, as He is the All-Knower.) meaning, find out about Him from one who knows most about Him, and follow him and take him as your example. It is known that there is no one who knows more about Allah than His servant and Messenger Muhammad, the absolute leader of the sons of Adam in this world and the Hereafter, who does not speak of his own desire, but conveys revelation revealed to him. What he says is true, and he is the leader whose decision counts; when there is a dispute, people are obliged to refer to him, and whatever is in accordance with his words and deeds is right, and whatever goes against them should be rejected no matter who says or does it. Allah says:
فَإِن تَنَازَعْتُمْ فِى شَىْءٍ
((And) if you differ in anything among yourselves...) (4:59).
(And when it is said to them: "Prostrate yourselves to Ar-Rahman!'' They say: "And what is Ar-Rahman'') meaning: we do not know Ar-Rahman. They did not like to call Allah by His Name Ar-Rahman (the Most Gracious), as they objected on the day of (the treaty of) Al-Hudaybiyyah, when the Prophet told the scribe:
«اكْتُبْ بِسْمِ اللهِ الرَّحْمنِ الرَّحِيم»
(Write: "In the Name of Allah, Ar-Rahman (the Most Gracious), Ar-Rahim (the Most Merciful).'') They said, "We do not know Ar-Rahman or Ar-Rahim. Write what you used to write: `Bismika Allahumma (in Your Name, O Allah).''' So Allah revealed the words:
(Say: "Invoke Allah or invoke Ar-Rahman, by whatever name you invoke Him (it is the same), for to Him belong the Best Names) (17:110). meaning, He is Allah and He is the Most Gracious. And in this Ayah, Allah said:
(And when it is said to them: "Prostrate yourselves to Ar-Rahman!'' They say: "And what is the Ar-Rahman'') meaning: we do not know or approve of this Name.
أَنَسْجُدُ لِمَا تَأْمُرُنَا
(Shall we fall down in prostration to that which you command us) means, "Just because you tell us to''
(And it increases in them only aversion.) As for the believers, they worship Allah Who is the Most Gracious, Most Merciful, and they attribute divinity to Him Alone and prostrate to Him. The scholars, agree that it is allowed and approved for the reader and the listener to prostrate when he reaches this mention of prostration in Surat Al-Furqan, and Allah knows best.
Maududi - Sayyid Abul Ala Maududi - Tafhim al-Qur'an
This verse (56) was meant to comfort the Holy Prophet and to warn the disbelievers who opposed him and obstructed his work, as if to say, "Your duty is only to convey the Message of good news to the people and to warn them of the consequences of disbelief: you are not responsible as to whether they accept.your Message or reject it, or to reward the Believers and punish the disbelievers."
Such words occur in the Qur'an at other places also and are obviously directed to the disbelievers, as if to say, "The Message of the Prophet is meant to reform the people without any tinge of selfishness. As he does not force the people to accept his Message, there is no reason why you should feel offended. If you accept the Message, it will be for your own good, and if you reject it, you will be harming yourselves alone. For after conveying the Message, he is relieved of his duty and responsibility; then the matter will be between you and Us."
Although this is a very simple and clear interpretation of verse 56 (and of similar other verses), yet some people erroneously conclude from it that the only duty and responsibility of the Prophet is to convey the Message and nothing else. They forget that the Qur'an has stressed over and over again that the Prophet is not only a giver of good news to the Believers but he is also their teacher, their lawgiver, judge and guide, a purifier of their morals and a model of life for them, and that every word which he utters is law which they have to obey and follow willingly in all walks of life and for all times to come.