Imaam Sadi (rahimahullaah) said:

And had it been that there was nothing else from the miracles of the Messengers other than the religion they were sent with, then this would have (sufficed) as the greatest evidence that the religion is from Allaah because of its (perfect) rulings and regulations, which (perfectly) measures all beneficial affairs and the truthfulness of its information in every era; its command towards every good and prohibition of every evil.  Every Messenger (spoke) about the truthfulness of the (other) Messenger who came before him or was to come after him and bore witness for him.

And from the special miracles of Prophet Hud (alayhis-salaam) was that he was alone in carrying out his call; (alone) in discrediting their superstitions; declaring them misguided and rebuking their idols.  They were a people of violence, strength and tyranny, and indeed they did threaten him with their idols that he will be afflicted with madness or evil if he did not stop (calling them to Tawheed); so (Allaah informed us that Hud) challenged them in public and said to them openly:

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).’’ [Hood; Ayaat: 54-56]

They were not able to harm him, so what miracle can be greater than this challenge to those enemies- those who were eager to destroy his call through every means! And when their transgression was to come to an end, he turned away from them and warned them of the arrival of a punishment.  The punishment came upon at a time in which they were greatly in need of rain.  So when they rejoiced, as (Allaah) said:

[فَلَمَّا رَأَوۡهُ عَارِضً۬ا مُّسۡتَقۡبِلَ أَوۡدِيَتِہِمۡ قَالُواْ هَـٰذَا عَارِضٌ۬ مُّمۡطِرُنَا‌ۚ- ”Then, when they saw it as a dense cloud coming towards their valleys, they said: “This is a cloud bringing us rain!” but Allaah said: [بَلۡ هُوَ مَا ٱسۡتَعۡجَلۡتُم بِهِ- ”Nay, but it is that (torment) which you were asking to be hastened!” due to your saying to Hud: [فَأۡتِنَا بِمَا تَعِدُنَآ إِن كُنتَ مِنَ ٱلصَّـٰدِقِينَ -”Then bring us that with which you threaten us, if you are one of the truthful!] And Allaah said (about the punishment that finally came upon them): [رِيحٌ۬ فِيہَا عَذَابٌ أَلِيمٌ۬] ”A wind wherein is a painful torment!” [تُدَمِّرُ كُلَّ شَىۡءِۭ بِأَمۡرِ رَبِّہَا- ”Destroying everything by the Command of its Lord]’ [Ahqaaf: Ayaat: 22-25]

 ——————————————————–

[Source: Qisasul Anbiyaa: page: 70-71]