Surah Al-Hajj (The Pilgrimage), Verse 55

وَلَا یَزَالُ الَّذِیْنَ كَفَرُوْا فِیْ مِرْیَةٍ مِّنْهُ حَتّٰی تَاْتِیَهُمُ السَّاعَةُ بَغْتَةً اَوْ یَاْتِیَهُمْ عَذَابُ یَوْمٍ عَقِیْمٍ ۟

Wa laa yazaalul lazeena kafaroo fee miryatim minhu hattaa taatiyahumus Saa'atu baghtatan aw yaatiyahum 'azaabu Yawmin 'aqeem

“Those who reject Faith will not cease to be in doubt concerning (Revelation) until the Hour (of Judgment) comes suddenly upon them, or there comes to them the Penalty of a Day of Disaster.”

Quran 22:55 (Yusuf Ali Translation)