Tafsir of Al-Fajr 89:7

Saw you not how your Lord dealt with `Ad Iram of the pillars, These were the first people of `Ad. They were the descendants of `Ad bin Iram bin `Aws bin Sam bin Nuh. This was said by Ibn Ishaq. They are those to whom Allah sent His Messenger Hud. However, they rejected and opposed him. Therefore, Allah saved him and those who believed with him from among them, and He destroyed others with a furious, violent wind

سخرها عليهم سبع ليال وثمنية أيام حسوما فترى القوم فيها صرعى كٲنهم أعجاز نخل خاوية

فهل ترى لهم من باقية

Which Allah imposed on them for seven nights and eight days in succession, so that you could see men lying overthrown, as if they were hollow trunks of date palms! Do you see any remnants of them? (69: 7-8) Allah mentioned their story in the Qur'an in more than one place, so that the believers may learn a lesson from their demise. Allah then says,

إرم ذات العماد

(Iram of the pillars). This is an additional explanation that adds clarification who they actually were. Concerning His saying,

ذات العماد

(of the pillars.) is because they used to live in trellised houses that were raised with firm pillars. They were the strongest people of their time in their physical stature, and they were the mightiest people in power. Thus, Hud reminded them of this blessing, and he directed them to use this power in the obedience of their Lord Who had created them. He said,

واذكروا إذ جعلكم خلفاء من بعد قوم نوح وزادكم فى الخلق بسطة فاذكروا ءاﻻء الله لعلكم تفلحون

And remember that He made you successors after the people of Nuh and increased you amply in stature. So remember the graces from Allah so that you may be successful.(7:69) Allah also said,

فٲما عاد فاستكبروا فى اﻻرض بغير الحق وقالوا من أشد منا قوة أولم يروا أن الله الذى خلقهم هو أشد منهم قوة

As for 'Ad, they were arrogant in the land without right, and they said: "Who is mightier than us in strength'' See they not that Allah Who created them was mightier in strength than them. (41:15) And Allah says here,

التي لم يخلق مثلها في البﻼد