Surah An Nisa Tafseer

وَمَن يَكْسِبْ إِثْمًا فَإِنَّمَا يَكْسِبُهُ عَلَى نَفْسِهِ

And whoever earns sin, he earns it only against himself.

is similar to His statement,

وَلَا تَزِرُ وَازِرَةٌ وِزْرَ أُخْرَى

And no bearer of burdens shall bear the burden of another. (35:18)

So no one will avail anyone else. Rather, every soul, and none else, shall carry its own burden.

This is why Allah said,

وَكَانَ اللّهُ عَلِيمًا حَكِيمًا

And Allah is Ever All-Knowing, All-Wise.

meaning, this occurs due to His knowledge, wisdom, fairness and mercy.

وَمَن يَكْسِبْ خَطِييَةً أَوْ إِثْمًا ثُمَّ يَرْمِ بِهِ بَرِييًا فَقَدِ احْتَمَلَ بُهْتَانًا وَإِثْمًا مُّبِينًا