The Quran

أَو كَظُلُماتٍ في بَحرٍ لُجِّيٍّ يَغشاهُ مَوجٌ مِن فَوقِهِ مَوجٌ مِن فَوقِهِ سَحابٌ ۚ ظُلُماتٌ بَعضُها فَوقَ بَعضٍ إِذا أَخرَجَ يَدَهُ لَم يَكَد يَراها ۗ وَمَن لَم يَجعَلِ اللَّهُ لَهُ نورًا فَما لَهُ مِن نورٍ

Muhammad Asad

Or [else, their deeds¹ are] like the depths of darkness upon an abysmal sea, made yet more dark by wave billowing over wave, with [black] clouds above it all: depths of darkness, layer upon layer,² [so that when one holds up his hand, he can hardly see it: for he to whom God gives no light, no light whatever has he!

I.e., their bad deeds, as contrasted with their good deeds, which in the preceding verse have been likened to a mirage.
Lit., "one above another",