Al An‘ām

وَلِكُلٍّ دَرَجَاتٌ مِّمَّا عَمِلُواْ وَمَا رَبُّكَ بِغَافِلٍ عَمَّا يَعْمَلُونَ

132. "And for all (men) there are ranks in accordance with what they have done, and your Lord is not heedless of what they do."

Allah is just and He gives everyone the rank due to the deeds the one has performed. Thus, both the felicity and evil fortune of people depend on their own deeds and conduct.