«يؤتى للمؤمنين بأيمانهم، والكفار بشمائلهم ووراء ظهورهم»
“Believers will be given their records in their right hands, while disbelievers will receive them in their left hands and behind their backs.”
Both the left hand and behind the back occur in descriptions of loss and disgrace. There is no need to invent a precise physical reconstruction of how those expressions jointly apply.
The contrast is not about the mechanics of receiving paper alone; it reflects the difference in the final accounting and its consequences.