يَا أَيُّهَا النَّاسُ إِنَّ وَعْدَ اللَّهِ حَقٌّO mankind!Verily, the promise of Allah is true.meaning the Resurrection will undoubtedly come to pass.فَلَ تَغُرَّنَّكُمُ الْحَيَاةُ الدُّنْيَاSo, 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.'وَلَا يَغُرَّنَّكُم بِاللَّهِ الْغَرُورُand 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 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:فَلَ تَغُرَّنَّكُمُ الْحَيَوةُ الدُّنْيَا وَلَا يَغُرَّنَّكُم بِاللَّهِ الْغَرُورُlet 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