Q 11:62

They said: "O Salih! You have been among us as a figure of good hope until this! Do you (now) forbid us the worship of what our fathers have worshipped? But we are really in grave doubt as to that to which you invite us. (62)He said: "O my people! Tell me, if I have a clear proof from my Lord, and there has come to me a mercy from Him, who then can help me against Allah, if I were to disobey Him? Then you increase me not but in loss. (63) The Conversation between Salih and the People of Thamud Allah, the Exalted, mentions what transpired in the discussion between Salih and his people. Allah informs of their ignorance and obstinacy in their statement, قَدْ كُنتَ فِينَا مَرْجُوًّا قَبْلَ هَٰذَا (You have been among us as a figure of good hope till this!) They were saying in this, "We had hope in your strong intellect before you began saying what you have said." أَتَنْهَانَا أَن نَّعْبُدَ مَا يَعْبُدُ آبَاؤُنَا (Do you (now) forbid us the worship of what our fathers have worshipped?) "what those who were before us were upon." وَإِنَّنَا لَفِي شَكٍّ مِّمَّا تَدْعُونَا إِلَيْهِ مُرِيبٍ (But we are really in grave doubt as to that which you invite us.) This alludes to the great amount of doubt that they had. قَالَ يَا قَوْمِ أَرَأَيْتُمْ إِن كُنتُ عَلَىٰ بَيِّنَةٍ مِّن رَّبِّي (He said: "O my people! Tell me, if I have a clear proof from my Lord...") 'In reference to what He (Allah) has sent me with to you, I am upon conviction and sure evidence.' وَآتَانِي مِنْهُ رَحْمَةً فَمَن يَنصُرُنِي مِنَ اللَّهِ إِنْ عَصَيْتُهُ (and there has come to me a mercy from Him, who then can help me against Allah, if I were to disobey Him?) 'and abandon calling you to the truth and the worship of Allah alone. If I did so, you would not be able to bring me any benefit, nor increase me غَيْرَ تَخْسِيرٍ (but in loss.)' This means loss and ruin.