Quran 2:55 from Surah Al-Baqara on Divine Marvels.
وَإِذۡ قُلۡتُمۡ يَٰمُوسَىٰ لَن نُّؤۡمِنَ لَكَ حَتَّىٰ نَرَى ٱللَّهَ جَهۡرَةٗ فَأَخَذَتۡكُمُ ٱلصَّٰعِقَةُ وَأَنتُمۡ تَنظُرُونَ
English translation: And when you said O Musa Never (will) we believe in you until we see Allah manifestly So seized you the thunderbolt while you (were) looking
Transliteration: wa-idh qul'tum yamusa lan nu'mina laka hatta nara al-laha jahratan fa-akhadhatkumu al-sa'iqatu wa-antum tanzuruna