[as if] to prove their ingratitude for all that We have granted them! Enjoy, then, your [brief] life: but in time you will come to know [the truth]!

(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)!

So as to deny that which We have given them. Then enjoy life (while ye may), for ye will come to know.

So as to deny what We have given them. Then enjoy yourselves, for soon will you know.

So they will deny what We have given them. Then enjoy yourselves, for you are going to know.