Qur'an 4:93

وَمَن يَقْتُلْ مُؤْمِنًا مُّتَعَمِّدًا فَجَزَآؤُهُۥ جَهَنَّمُ خَـٰلِدًا فِيهَا وَغَضِبَ ٱللَّهُ عَلَيْهِ وَلَعَنَهُۥ وَأَعَدَّ لَهُۥ عَذَابًا عَظِيمًا

“But whoever kills a believer intentionally - his recompense is Hell, wherein he will abide eternally, and Allāh has become angry with him and has cursed him and has prepared for him a great punishment.”

An-Nisaa 4:93 · Saheeh International