In The Name of Allaah, The Most Merciful, The Bestower of Mercy.

Allaah [The Exalted] said:

وَإِلَىٰ عَادٍ أَخَاهُمۡ هُودً۬ا‌ۚ قَالَ يَـٰقَوۡمِ ٱعۡبُدُواْ ٱللَّهَ مَا لَڪُم مِّنۡ إِلَـٰهٍ غَيۡرُهُ ۥۤ‌ۖ إِنۡ أَنتُمۡ إِلَّا مُفۡتَرُونَ

يَـٰقَوۡمِ لَآ أَسۡـَٔلُكُمۡ عَلَيۡهِ أَجۡرًا‌ۖ إِنۡ أَجۡرِىَ إِلَّا عَلَى ٱلَّذِى فَطَرَنِىٓ‌ۚ أَفَلَا تَعۡقِلُونَ

وَيَـٰقَوۡمِ ٱسۡتَغۡفِرُواْ رَبَّكُمۡ ثُمَّ تُوبُوٓاْ إِلَيۡهِ يُرۡسِلِ ٱلسَّمَآءَ عَلَيۡڪُم مِّدۡرَارً۬ا وَيَزِدۡڪُمۡ قُوَّةً إِلَىٰ قُوَّتِكُمۡ وَلَا تَتَوَلَّوۡاْ مُجۡرِمِينَ

قَالُواْ يَـٰهُودُ مَا جِئۡتَنَا بِبَيِّنَةٍ۬ وَمَا نَحۡنُ بِتَارِكِىٓ ءَالِهَتِنَا عَن قَوۡلِكَ وَمَا نَحۡنُ لَكَ بِمُؤۡمِنِينَ

إِن نَّقُولُ إِلَّا ٱعۡتَرَٮٰكَ بَعۡضُ ءَالِهَتِنَا بِسُوٓءٍ۬‌ۗ قَالَ إِنِّىٓ أُشۡہِدُ ٱللَّهَ وَٱشۡہَدُوٓاْ أَنِّى بَرِىٓءٌ۬ مِّمَّا تُشۡرِكُونَ

مِن دُونِهِۦ‌ۖ فَكِيدُونِى جَمِيعً۬ا ثُمَّ لَا تُنظِرُونِ

إِنِّى تَوَكَّلۡتُ عَلَى ٱللَّهِ رَبِّى وَرَبِّكُم‌ۚ مَّا مِن دَآبَّةٍ إِلَّا هُوَ ءَاخِذُۢ بِنَاصِيَتِہَآ‌ۚ إِنَّ رَبِّى عَلَىٰ صِرَٲطٍ۬ مُّسۡتَقِيمٍ۬

فَإِن تَوَلَّوۡاْ فَقَدۡ أَبۡلَغۡتُكُم مَّآ أُرۡسِلۡتُ بِهِۦۤ إِلَيۡكُمۡ‌ۚ وَيَسۡتَخۡلِفُ رَبِّى قَوۡمًا غَيۡرَكُمۡ وَلَا تَضُرُّونَهُ ۥ شَيۡـًٔا‌ۚ إِنَّ رَبِّى عَلَىٰ كُلِّ شَىۡءٍ حَفِيظٌ۬

وَلَمَّا جَآءَ أَمۡرُنَا نَجَّيۡنَا هُودً۬ا وَٱلَّذِينَ ءَامَنُواْ مَعَهُ ۥ بِرَحۡمَةٍ۬ مِّنَّا وَنَجَّيۡنَـٰهُم مِّنۡ عَذَابٍ غَلِيظٍ۬

وَتِلۡكَ عَادٌ۬‌ۖ جَحَدُواْ بِـَٔايَـٰتِ رَبِّہِمۡ وَعَصَوۡاْ رُسُلَهُ ۥ وَٱتَّبَعُوٓاْ أَمۡرَ كُلِّ جَبَّارٍ عَنِيدٍ۬

وَأُتۡبِعُواْ فِى هَـٰذِهِ ٱلدُّنۡيَا لَعۡنَةً۬ وَيَوۡمَ ٱلۡقِيَـٰمَةِ‌ۗ أَلَآ إِنَّ عَادً۬ا كَفَرُواْ رَبَّہُمۡ‌ۗ أَلَا بُعۡدً۬ا لِّعَادٍ۬ قَوۡمِ هُودٍ۬

And to ‘Ad (people We sent) their brother Hud. He said, “O my people! Worship Allah! You have no other Ilah (God) but Him. Certainly, you do nothing but invent (lies)! “O my people I ask of you no reward for it (the Message). My reward is only from Him, Who created me. Will you not then understand? “And O my people! Ask forgiveness of your Lord and then repent to Him, He will send you (from the sky) abundant rain, and add strength to your strength, so do not turn away as criminals”.  They said: “O Hud! No evidence have you brought us, and we shall not leave our gods for your (mere) saying! And we are not believers in you. “All that we say is that some of our gods (false deities) have seized you with evil (madness).” He said: “I call Allah to witness and bear you witness that I am free from that which you ascribe as partners in worship – with Him (Allah). So plot against me, all of you, and give me no respite. “I put my trust in Allah, my Lord and your Lord! There is not a moving (living) creature but He has grasp of its forelock. Verily, my Lord is on the Straight Path (the truth). “So if you turn away, still I have conveyed the Message with which I was sent to you. My Lord will make another people succeed you, and you will not harm Him in the least. Surely, my Lord is Guardian over all things.” And when Our Commandment came, We saved Hud and those who believed with him by a Mercy from Us, and We saved them from a severe torment. Such were ‘Ad (people). They rejected the Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) of their Lord and disobeyed His Messengers, and followed the command of every proud obstinate (oppressor of the truth, from their leaders). And they were pursued by a curse in this world and (so they will be) on the Day of Resurrection. No doubt! Verily, ‘Ad disbelieved in their Lord. So away with ‘Ad, the people of Hud. [Surah Hud. Aayaat 50-60]

Allaah [The Exalted] said that they said to Hud [peace and blessings of Allaah be upon him]: [إِن نَّقُولُ إِلَّا ٱعۡتَرَٮٰكَ بَعۡضُ ءَالِهَتِنَا بِسُوٓءٍ۬‌ – All that we say is that some of our gods (false deities) have seized you with evil (madness)]- Meaning, “Our gods have afflicted you with dementia and insanity, therefore you have started mumbling that which cannot be understood”. Glorified be Allaah Who placed a covering on the hearts of the wrongdoers! How could they consider the most truthful one amongst the people who brought the most truthful of truthful affairs to be at this level, which a sensible person would have been ashamed to narrate from them had it not been that Allaah informed us of it. This is why Hud [alayhis salaam] made it very clear to them that he was absolutely certain that neither can they nor their idols harm him, as Allaah stated that Hud [peace and blessings of Allaah be upon him] said:

قَالَ إِنِّىٓ أُشۡہِدُ ٱللَّهَ وَٱشۡہَدُوٓاْ أَنِّى بَرِىٓءٌ۬ مِّمَّا تُشۡرِكُونَ

مِن دُونِهِۦ‌ۖ فَكِيدُونِى جَمِيعً۬ا ثُمَّ لَا تُنظِرُونِ

إِنِّى تَوَكَّلۡتُ عَلَى ٱللَّهِ رَبِّى وَرَبِّكُم‌ۚ مَّا مِن دَآبَّةٍ إِلَّا هُوَ ءَاخِذُۢ بِنَاصِيَتِہَآ‌ۚ إِنَّ رَبِّى عَلَىٰ صِرَٲطٍ۬ مُّسۡتَقِيمٍ۬

“I call Allah to witness and bear you witness that I am free from that which you ascribe as partners in worship – with Him (Allah). So plot against me, all of you, and give me no respite. “I put my trust in Allah, my Lord and your Lord! There is not a moving (living) creature but He has grasp of its forelock. Verily, my Lord is on the Straight Path (the truth).

 فَإِن تَوَلَّوۡاْ فَقَدۡ أَبۡلَغۡتُكُم مَّآ أُرۡسِلۡتُ بِهِۦۤ إِلَيۡكُمۡ‌ۚ وَيَسۡتَخۡلِفُ رَبِّى قَوۡمًا غَيۡرَكُمۡ وَلَا تَضُرُّونَهُ ۥ شَيۡـًٔا‌ۚ إِنَّ رَبِّى عَلَىٰ كُلِّ شَىۡءٍ حَفِيظٌ۬

وَلَمَّا جَآءَ أَمۡرُنَا نَجَّيۡنَا هُودً۬ا وَٱلَّذِينَ ءَامَنُواْ مَعَهُ ۥ بِرَحۡمَةٍ۬ مِّنَّا وَنَجَّيۡنَـٰهُم مِّنۡ عَذَابٍ غَلِيظٍ۬

وَتِلۡكَ عَادٌ۬‌ۖ جَحَدُواْ بِـَٔايَـٰتِ رَبِّہِمۡ وَعَصَوۡاْ رُسُلَهُ ۥ وَٱتَّبَعُوٓاْ أَمۡرَ كُلِّ جَبَّارٍ عَنِيدٍ۬

وَأُتۡبِعُواْ فِى هَـٰذِهِ ٱلدُّنۡيَا لَعۡنَةً۬ وَيَوۡمَ ٱلۡقِيَـٰمَةِ‌ۗ أَلَآ إِنَّ عَادً۬ا كَفَرُواْ رَبَّہُمۡ‌ۗ أَلَا بُعۡدً۬ا لِّعَادٍ۬ قَوۡمِ هُودٍ۬

“So if you turn away, still I have conveyed the Message with which I was sent to you. My Lord will make another people succeed you, and you will not harm Him in the least. Surely, my Lord is Guardian over all things.” And when Our Commandment came, We saved Hud and those who believed with him by a Mercy from Us, and We saved them from a severe torment. Such were ‘Ad (people). They rejected the Ayat (proofs, evidences, verses, lessons, signs, revelations, etc.) of their Lord and disobeyed His Messengers, and followed the command of every proud obstinate (oppressor of the truth, from their leaders). And they were pursued by a curse in this world and (so they will be) on the Day of Resurrection. No doubt! Verily, ‘Ad disbelieved in their Lord. So away with ‘Ad, the people of Hud. [An Excerpt from Tafseer As-Sadi. Slightly paraphrased]