Key Verses

1. 2:178Al-BaqarahWarning
   يَـٰٓأَيُّهَا ٱلَّذِينَ ءَامَنُواْ كُتِبَ عَلَيۡكُمُ ٱلۡقِصَاصُ فِي ٱلۡقَتۡلَىۖ ٱلۡحُرُّ بِٱلۡحُرِّ وَٱلۡعَبۡدُ بِٱلۡعَبۡدِ وَٱلۡأُنثَىٰ بِٱلۡأُنثَىٰۚ فَمَنۡ عُفِيَ لَهُۥ مِنۡ أَخِيهِ شَيۡءٞ فَٱتِّبَاعُۢ بِٱلۡمَعۡرُوفِ وَأَدَآءٌ إِلَيۡهِ بِإِحۡسَٰنٖۗ ذَٰلِكَ تَخۡفِيفٞ مِّن رَّبِّكُمۡ وَرَحۡمَةٞۗ فَمَنِ ٱعۡتَدَىٰ بَعۡدَ ذَٰلِكَ فَلَهُۥ عَذَابٌ أَلِيمٞ
   O ye who believe! Retaliation is prescribed for you in the matter of the murdered; the freeman for the freeman, and the slave for the slave, and the female for the female. And for him who is forgiven somewhat by his (injured) brother, prosecution according to usage and payment unto him in kindness. This is an alleviation and a mercy from your Lord. He who transgresseth after this will have a painful doom.
   In context

   O you who have faith in Allah and follow His Messenger, it is decreed for you that in cases where someone deliberately attacks and kills someone, the punishment for the murderer should be the same as their crime: the freeman killed for the freeman; the slave for the slave; and the female for the female.

2. 4:157An-Nisa
   وَقَوۡلِهِمۡ إِنَّا قَتَلۡنَا ٱلۡمَسِيحَ عِيسَى ٱبۡنَ مَرۡيَمَ رَسُولَ ٱللَّهِ وَمَا قَتَلُوهُ وَمَا صَلَبُوهُ وَلَٰكِن شُبِّهَ لَهُمۡۚ وَإِنَّ ٱلَّذِينَ ٱخۡتَلَفُواْ فِيهِ لَفِي شَكّٖ مِّنۡهُۚ مَا لَهُم بِهِۦ مِنۡ عِلۡمٍ إِلَّا ٱتِّبَاعَ ٱلظَّنِّۚ وَمَا قَتَلُوهُ يَقِينَۢا
   And because of their saying: We slew the Messiah, Jesus son of Mary, Allah's messenger - they slew him not nor crucified him, but it appeared so unto them; and lo! those who disagree concerning it are in doubt thereof; they have no knowledge thereof save pursuit of a conjecture; they slew him not for certain.
   In context

   I cursed them because they proudly, but falsely, said, ‘We killed the Messiah, Jesus, son of Mary, the messenger of Allah’. They did not kill him as they claimed, nor did they crucify him; but they killed and crucified a man whom Allah made to resemble Jesus, so they thought the person who was killed was Jesus.