Quran 2:91 from Surah Al-Baqara on Divine Marvels.
وَإِذَا قِيلَ لَهُمۡ ءَامِنُواْ بِمَآ أَنزَلَ ٱللَّهُ قَالُواْ نُؤۡمِنُ بِمَآ أُنزِلَ عَلَيۡنَا وَيَكۡفُرُونَ بِمَا وَرَآءَهُۥ وَهُوَ ٱلۡحَقُّ مُصَدِّقٗا لِّمَا مَعَهُمۡۗ قُلۡ فَلِمَ تَقۡتُلُونَ أَنۢبِيَآءَ ٱللَّهِ مِن قَبۡلُ إِن كُنتُم مُّؤۡمِنِينَ
English translation: And when it is said to them Believe in what has revealed Allah they say We believe in what was revealed to us And they disbelieve in what (is) besides it while it (is) the truth confirming what (is) with them Say Then why (did) you kill (the) Prophets (of) Allah from before if you were believers
Transliteration: wa-idha qila lahum aminu bima anzala al-lahu qalu nu'minu bima unzila alayna wayakfuruna bima waraahu wahuwa al-haqu musaddiqan lima ma'ahum qul falima taqtuluna anbiyaa al-lahi min qablu in kuntum mu'minina