Then Allah says,

هَذَا يَوْمُ الْفَصْلِ جَمَعْنَاكُمْ وَالْأَوَّلِينَ ﴿٣٨﴾

فَإِن كَانَ لَكُمْ كَيْدٌ فَكِيدُونِ ﴿٣٩﴾

وَيْلٌ يَوْمَئِذٍ لِّلْمُكَذِّبِينَ ﴿٤٠﴾

That will be a Day of Decision! We have brought you and the men of old together! So if you have a plot, use it against Me!

This is an address from the Creator to His servants. He says to them, هَذَا يَوْمُ الْفَصْلِ جَمَعْنَاكُمْ وَالْأَوَّلِينَ (That will be a Day of Decision! We have brought you and the men of old together!)

meaning, He will gather all of them by His power on one common plane, He will make them hear the caller and He will cause them to see.

Then He says, فَإِن كَانَ لَكُمْ كَيْدٌ فَكِيدُونِ (So, if you have a plot, use it against Me!)

This is a serious threat and a harsh warning. It means, `if you are able to save yourselves from being seized by Me, and rescue yourselves from My ruling, then do so. But you are certainly not able to do so.' This is as Allah says,

يمَعْشَرَ الْجِنِّ وَالإِنسِ إِنِ اسْتَطَعْتُمْ أَن تَنفُذُواْ مِنْ أَقْطَـرِ السَّمَـوَتِ وَالاٌّرْضِ فَانفُذُواْ لاَ تَنفُذُونَ إِلاَّ بِسُلْطَـنٍ

O assembly of Jinn and men! If you have power to pass beyond the zones of the heavens and the earth, then pass beyond (them)! But you will never be able to pass them, except with authority (from Allah)! (55:33)

Allah also says,

وَلاَ تَضُرُّونَهُ شَيْئًا

And you will not harm Him in the least. (11:57)

It is narrated in a Hadith (that Allah said),

يَا عِبَادِي،

إِنَّكُمْ لَنْ تَبْلُغُوا نَفْعِي فَتَنْفَعُونِي،

وَلَنْ تَبْلُغُوا ضَرِّي فَتَضُرُّونِي

"O My servants!

You all can never attain My benefit and thereby benefit Me, and

you all can never attain My harm and thereby harm Me.''