العنكبوت — Al-'Ankabut Ayat 18
وَاِنْ تُكَذِّبُوْا فَقَدْ كَذَّبَ اُمَمٌ مِّنْ قَبْلِكُمْ ۗوَمَا عَلَى الرَّسُوْلِ اِلَّا الْبَلٰغُ الْمُبِيْنُ
Wa in tukażżibū faqad każżaba umamum min qablikum, wa mā ‘alar-rasūli illal-balāgul-mubīn(u).
"And if you [people] deny [the message] - already nations before you have denied. And there is not upon the Messenger except [the duty of] clear notification."