As-Saaffaat • EN-AL-JALALAYN
﴿ إِذْ قَالَ لِقَوْمِهِۦٓ أَلَا تَتَّقُونَ ﴾
“when he spoke [thus] to his people: “Will you not remain conscious of God?”
When idh is dependent because of an implicit verb udhkur ‘mention’ he said to his people ‘Will you not fear God?