(… بِإِثْمِي وَإِثْمِكَ …) (…my sin and your sin …): The sin of murdering me, in addition to your previous sin of presenting the worst ram.

(  فَتَكُونَ مِنْ أَصْحَابِ النَّارِ ۚ وَذَٰلِكَ جَزَاءُ الظَّالِمِينَ … ) (…so you will be among the companions of the Fire. And that is the recompense of wrongdoers.): How did Abel know that Cain will be one of the dwellers of the Fire, and that is the recompense of the wrongdoers? Because he wronged himself and his brother.