After describing the two examples the next sentence says: وَمَن لَّمْ يَجْعَلِ اللَّـهُ لَهُ نُورًا فَمَا لَهُ مِن نُّورٍ(And the one to whom Allah does not give light can have no light at all - 40).
This sentence about the disbelievers is like the one that appeared earlier for the believers: يَهْدِي اللَّـهُ لِنُورِهِ مَن يَشَاءُ (Allah guides to His light whomsoever He wills — An-Nur 24:35 ⧉). It describes the deprivation of disbelievers from the Nur of guidance, which they lost by denying the injunctions of Allah, and when they have lost Allah's Nur of guidance how can they get any other Nur.
This verse An-Nur 24:40 ⧉ also explains that no one can become a perspicacious scholar merely by having resource of insight and knowledge, rather it is bestowed by the grace of Allah only. It is for this reason that those who are regarded naive in mundane matters prove themselves very knowledgeable and scholarly in the cognizance of the Hereafter. And, vice versa, many who are regarded very intelligent and knowledgeable in worldly matters, prove themselves completely ignorant and foolish in the perception and comprehension of the Hereafter. (Mazhari)