يَٰٓأَيُّهَا ٱلنَّاسُ إِنَّ وَعْدَ ٱللَّهِ حَقٌّ فَلَا تَغُرَّنَّكُمُ ٱلْحَيَوٰةُ ٱلدُّنْيَا وَلَا يَغُرَّنَّكُم بِٱللَّهِ ٱلْغَرُورُ · إِنَّ ٱلشَّيْطَٰنَ لَكُمْ عَدُوٌّ فَٱتَّخِذُوهُ عَدُوًّا
"O people! God's promise is true. Do not let the life of this world deceive you; and do not let the great deceiver deceive you with God. Satan is an enemy to you; so take him as an enemy."
The same root occurs in three words: taghurrannakum (let it not deceive you), yaghurrannakum (let him not deceive you), al-gharūr (the great deceiver).
The lexicographers give the concrete sense of the root thus: that the outward look of a thing should be striking while its inside is empty. Ghirr — the inexperienced youth; ghurūr — a misleading appearance.
بِٱللَّهِ — and the particle is worth recording: yaghurrannakum billāhi — "let him not deceive you with God."
I record this as my own reading: the verse says that deceiving can be done by using the name of God. That is: deception does not always come by way of denial; it can come also by pulling forgiveness to the wrong place. And in al-Zumar at 39/53 it was commanded that hope of forgiveness not be cut off — read together, the two verses set up a balance: despair is forbidden, and so is leaning back on assurance.
The logic of the sentence is worth recording: the enmity is already there (inna'sh-shayṭāna lakum ʿaduww) — what is commanded is that this enmity be made mutual.
That is: the verse is not content to give a piece of information; it asks for what the information requires. I record this as an observation: the difference between knowing a danger and behaving accordingly has been distributed over the two halves of the sentence.