Quran 6:28 from Surah Al-An'aam on Divine Marvels.
بَلۡ بَدَا لَهُم مَّا كَانُواْ يُخۡفُونَ مِن قَبۡلُۖ وَلَوۡ رُدُّواْ لَعَادُواْ لِمَا نُهُواْ عَنۡهُ وَإِنَّهُمۡ لَكَٰذِبُونَ
English translation: Nay became manifest for them what they used to conceal from before And if they were sent back certainly they (would) return to what they were forbidden from it and indeed they certainly are liars
Transliteration: bal bada lahum ma kanu yukh'funa min qablu walaw ruddu la'adu lima nuhu anhu wa-innahum lakadhibuna