Surah 82. Al-Infitar, Ayah 5

I.e., what he has done and what he has omitted to do. An alternative rendering would be, "what he has placed forward and what he has placed behind", i.e., what he prized more and what less in his erstwhile, subjective valuation. Thus, at the moment of resurrection man will suddenly understand the true motivations and moral implications of whatever he did - or consciously refrained from doing - during his life in this world: and this applies to all the good deeds he did and the sins he refrained from, as well as to all the sins he committed and the good deeds he failed to do.

Sent Forward and kept back: may mean: the deeds of commission and omission in this life. Or the Arabic words may also be translated: sent forward and left behind: i.e., the spiritual possibilities which it sent forward for its other life, and the physical things on which it prided itself in this life, but which it had to leave behind in this fife. Or else, the things it put first and the things it put last in importance may change places in the new world of Reality. "The first shall be last and the last shall be first".