Surah Al-A'raf (The Heights), Verse 93

فَتَوَلّٰی عَنْهُمْ وَقَالَ یٰقَوْمِ لَقَدْ اَبْلَغْتُكُمْ رِسٰلٰتِ رَبِّیْ وَنَصَحْتُ لَكُمْ فَكَیْفَ اٰسٰی عَلٰی قَوْمٍ كٰفِرِیْنَ 

Fatawalla 'anhum wa qaala yaa qawmi laqad ablaghtukum Risaalaati Rabbee wa nasahtu lakum fakaifa aasaa'alaa qawmin kaafireen

“So Shu'aib left them, saying: "O my people! I did indeed convey to you the messages for which I was sent by my Lord: I gave you good counsel, but how shall I lament over a people who refuse to believe!"”

Quran 7:93 (Yusuf Ali Translation)