for We shall have turned towards all the [supposedly good] deeds they ever wrought, and shall have transformed them into scattered dust

And We shall turn to whatever deeds they did (in this life), and We shall make such deeds as floating dust scattered about.

And We shall turn unto the work they did and make it scattered motes.

And We shall turn to the work they have done, so We shall render it as scattered motes.

And We will regard what they have done of deeds and make them as dust dispersed.