﴿ وَثَمُودَ ٱلَّذِينَ جَابُوا۟ ٱلصَّخْرَ بِٱلْوَادِ ﴾

“and with [the tribe of] Thamud, who hollowed out rocks in the valley? –”

and Thamūd who hollowed hewed the rocks sakhr is the plural of sakhra in the valley the Wādī al-Qurā rocks which they used as dwellings