Abdul-Rahman bin Abza instructed me to ask Ibn Abbas about these two verses, "And whoever kills a believer intentionally, his recompense is Hell, abiding therein eternally" [Nisa 4:93].I asked him, and he said, "Nothing has abrogated it."I also asked him about this verse, "And those who do not invoke another god along with Allah, nor kill the soul which Allah has forbidden except in the course of justice" [Furqan 25:68].He said, "It was revealed concerning the polytheists."
أمرني عبد الرحمن بن أبزى أن أسأل ابن عباس عن هاتين الآيتين: {ومن يقتل مؤمنا متعمدا فجزاؤه جهنم خلدا}، فسألته فقال: لم ينسخها شيء. وعن هذه الآية: {والذين لا يدعون مع الله إليها ءاخر ولا يقتلون النفس التي حرم الله إلا بالحق} [سورة الفرقان: ٦٨] قال: نزلت في أهل الشرك.
Bukhari reported it in the tafsir (4766), and Muslim reported it in the tafsir (18/3023), both of them through the route of Shubah, from Mansur, from Saeed bin Jubayr, who said, then he mentioned it. The wording given here is Muslim's, and Bukhari's wording is similar.