Allah says: `Even if these idolators who associate others with Allah disbelieve in you, O Muhammad, and go against the Message of Tawhid that you have brought, you have an example in the Messengers who came before you.' They also brought a clear Message to their people and told them to worship Allah alone, but their people denied them and went against them.
وَإِلَى اللَّهِ تُرْجَعُ الأُمُورُ
(And to Allah return all matters (for decision).) means, `We will requite them for that in full.' Then Allah says:
يأَيُّهَا النَّاسُ إِنَّ وَعْدَ اللَّهِ حَقٌّ
(O mankind! Verily, the promise of Allah is true.) meaning the Resurrection will undoubtedy come to pass.
فَلاَ تَغُرَّنَّكُمُ الْحَيَوةُ الدُّنْيَا
(So, let not this present life deceive you,) means, `this life is as nothing in compare to the great good that Allah has promised to His close friends and the followers of His Messengers, so do not let these transient attractions distract you from that which is lasting.'
وَلاَ يَغُرَّنَّكُم بِاللَّهِ الْغَرُورُ
(and let not the chief deceiver deceive you about Allah.) This refers to Shaytan, as stated by Ibn `Abbas, may Allah be pleased with him. Meaning, do not let the Shaytan tempt you and divert you away from following the Messengers of Allah ﷺ and believing what they say, for he is the chief deceiver and arch-liar. This Ayah is like the Ayah that appears at the end of Surah Luqman:
فَلاَ تَغُرَّنَّكُمُ الْحَيَوةُ الدُّنْيَا وَلاَ يَغُرَّنَّكُم بِاللَّهِ الْغَرُورُ
(let not then this (worldly) present life deceive you, nor let the chief deceiver deceive you about Allah) (31:33). Then Allah tells us of the enmity of Iblis towards the sons of Adam:
إِنَّ الشَّيْطَـنَ لَكُمْ عَدُوٌّ فَاتَّخِذُوهُ عَدُوّاً
(Surely, Shaytan is an enemy to you, so take (treat) him as an enemy.) meaning, `he has declared his enmity towards you, so be even more hostile towards him, oppose him and do not believe the things with which he tries to tempt you.'
إِنَّمَا يَدْعُو حِزْبَهُ لِيَكُونُواْ مِنْ أَصْحَـبِ السَّعِيرِ
(He only invites his followers that they may become the dwellers of the blazing Fire.) means, `he only wants to misguide you so that you will enter the blazing Fire with him.' This is a manifest enemy, and we ask Allah, the All-Powerful and Almighty to make us enemies of Shaytan and to make us followers of the Book of Allah and of the way of His Messengers. For He is able to do whatever He wills and He will respond to all supplication. This is like the Ayah:
وَإِذَا قُلْنَا لِلْمَلَـئِكَةِ اسْجُدُواْ لآِدَمَ فَسَجَدُواْ إِلاَّ إِبْلِيسَ كَانَ مِنَ الْجِنِّ فَفَسَقَ عَنْ أَمْرِ رَبِّهِ أَفَتَتَّخِذُونَهُ وَذُرِّيَّتَهُ أَوْلِيَآءَ مِن دُونِى وَهُمْ لَكُمْ عَدُوٌّ بِئْسَ لِلظَّـلِمِينَ بَدَلاً
(And (remember) when We said to the angels: "Prostrate yourselves unto Adam." So they prostrated themselves except Iblis. He was one of the Jinn; he disobeyed the command of his Lord. Will you then take him (Iblis) and his offspring as protectors and helpers rather than Me while they are enemies to you What an evil is the exchange for the wrongdoers.) (18:50)