Quran 41:13 from Surah Fussilat on Divine Marvels.
فَإِنۡ أَعۡرَضُواْ فَقُلۡ أَنذَرۡتُكُمۡ صَٰعِقَةٗ مِّثۡلَ صَٰعِقَةِ عَادٖ وَثَمُودَ
English translation: But if they turn away then say I have warned you (of) a thunderbolt like (the) thunderbolt (of) Aad and Thamud
Transliteration: fa-in a'radu faqul andhartukum sa'iqatan mith'la sa'iqati adin wathamuda