Tafsir of Al-Hijr 15:78-79

{The companions of the thicket} are the people of Shu‘ayb.

{And both of them} refers to the settlements of the people of Lot and the [companions of the] Thicket.

It is also said: The pronoun refers to the Thicket and Madyan, because Shu‘ayb was sent to both of them. When the Thicket was mentioned, its mention implied Madyan, so the pronoun for both was used.

{Are on a clear path} means on a manifest road. Al-Imam is a noun for that which is followed (as a guide). Thus, the road, the builder’s plumb line, and the tablet upon which one writes are all called imam, because they are things that are followed.

{And the companions of the rocky tract (al-Hijr) denied the messengers. And We gave them Our signs, but they were turning away from them. And they used to carve houses from the mountains, feeling secure. But the blast seized them at the morning. And what they used to earn did not avail them.}