Quran 6:157 from Surah Al-An'aam on Divine Marvels.
أَوۡ تَقُولُواْ لَوۡ أَنَّآ أُنزِلَ عَلَيۡنَا ٱلۡكِتَٰبُ لَكُنَّآ أَهۡدَىٰ مِنۡهُمۡۚ فَقَدۡ جَآءَكُم بَيِّنَةٞ مِّن رَّبِّكُمۡ وَهُدٗى وَرَحۡمَةٞۚ فَمَنۡ أَظۡلَمُ مِمَّن كَذَّبَ بِـَٔايَٰتِ ٱللَّهِ وَصَدَفَ عَنۡهَاۗ سَنَجۡزِي ٱلَّذِينَ يَصۡدِفُونَ عَنۡ ءَايَٰتِنَا سُوٓءَ ٱلۡعَذَابِ بِمَا كَانُواْ يَصۡدِفُونَ
English translation: Or you say If [that] was revealed to us the Book surely we (would) have been better guided than them So verily has come to you clear proofs from your Lord and a Guidance and a Mercy Then who (is) more unjust than (he) who denies [with] (the) Verses (of) Allah and turns away from them We will recompense those who turn away from Our Signs (with) an evil punishment because they used to turn away
Transliteration: aw taqulu law anna unzila alayna al-kitabu lakunna ahda min'hum faqad jaakum bayyinatun min rabbikum wahudan warahmatun faman azlamu mimman kadhaba biayati al-lahi wasadafa anha sanajzi alladhina yasdifuna an ayatina sua al-'adhabi bima kanu yasdifuna