لِيَكۡفُرُواْ بِمَآ ءَاتَيۡنَٰهُمۡ ۚ فَتَمَتَّعُواْ فَسَوۡفَ تَعۡلَمُونَ
(As if) to show their ingratitude for the (favours) We have bestowed on them! Then enjoy (your brief day); but soon will ye know (your folly).<br/>
Let them be ungrateful for what We have given them (this is [an imperative] meant as a threat). 'So take your enjoyment. Soon you will know', the consequences of your enjoyment (there is a shift away from the third person address to the second).