Surah 83. Al-Mutaffifin, Ayah 34

Speaking of the righteous, the Qur'an repeatedly stresses that on the Day of Judgment God "shall have removed whatever unworthy thoughts or feelings (ghill) may have been [lingering] in their bosoms" ( 7:43 and 15:47 ). Since an expression of vengeful joy on the part of the blest at the calamity which in the hereafter will befall the erstwhile sinners would certainly fall within the category of "unworthy feelings", their "laughing" can only have a metaphorical meaning, denoting no more than a realization of their own good fortune.

The tables will then be reversed, and he laughs best who laughs last.