"And you did your deed which you did," meaning: you killed the soul that you killed.
Muhammad said: The most excellent and common reading is (wa-fa'alta fa'lataka) with a fatha on the fa', because he intends: you killed the soul with your killing, according to the rule of a single instance. "And you are of the ungrateful," meaning: for our favor, that is: we raised you while you were small and were good to you.
﴿وَفعلت فعلتك الَّتِي فعلت﴾ يَعْنِي: وَقَتَلْتَ النَّفْسَ الَّتِي قَتَلْتَ.
قَالَ مُحَمَّدٌ: الْأَجْوَدُ فِي الْقِرَاءَةِ وَالْأَكْثَر: (وَفعلت فعلتك) بِفَتْحِ الْفَاءِ؛ لِأَنَّهُ يُرِيدُ: قَتَلْتَ النَّفْسَ قَتْلَتَكَ؛ عَلَى مَذْهَبِ الْمَرَّةِ الْوَاحِدَة. ﴿وَأَنت من الْكَافرين﴾ يَعْنِي: لِنِعْمَتِنَا، أَيْ: إِنَّا رَبَّيْنَاكَ صَغِيرا، وأحسنا إِلَيْك