Surah Al-Baqarah, ayah 91

2:91

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 ٩١

Wa idhā qīla lahum āminū bimā anzalallāhu qālū nu'minu bimā unzila 'alaynā wayakfurūna bimā warā'ahū wahuwal-haqqu musaddiqal limā ma'ahum qul falima taqtulūna ambiyā'allāhi min qablu in kuntum mu'minīn

And when it is said to them, "Believe in what Allāh has revealed," they say, "We believe [only] in what was revealed to us." And they disbelieve in what came after it, while it is the truth confirming that which is with them. Say, "Then why did you kill the prophets of Allāh before, if you are [indeed] believers?"