Tafsir of Al-Mutaffifeen 83:34-36

{On adorned couches, looking on} This is a circumstantial qualifier (ḥāl) for the verb {they laugh}. It means: they laugh at them while looking at them, and at the humiliation and disgrace they are in after their former pride and arrogance, and at the various types of torment they suffer after their former luxury and ease—all while they themselves are secure upon their couches.

It is also said: A door to Paradise is opened for the disbelievers, and it is said to them, "Come out toward it." When they reach it, it is shut against them. This is done to them repeatedly, and so the believers laugh at them.

{Has the disbeliever been rewarded...} Thawbahu (his reward) and athābahu (he rewarded him) have the same meaning: when one recompenses another. Aws [ibn Ḥajar] said:

I shall reward you, or you shall be rewarded by me with a recompense, And it is enough for you that you are praised and commended.

It has also been recited with the assimilation (idghām) of the lām into the thā’.

From the Messenger of Allah (ﷺ): "Whoever recites Sūrat al-Muṭaffifīn, Allah will give him to drink of the Sealed Nectar (al-raḥīq al-makhtūm) on the Day of Resurrection."