قُلْ أَعُوذُ بِرَبِّ النَّاسِ
Say: I seek refuge in the Lord of humankind. (114:1)
Al-nās is the genitive complement of rabb, establishing humankind as the repeated thematic reference of the surah. That noun will return in subsequent divine descriptions and in the account of whispering.
The choice contrasts contextually with al-Falaq’s “Lord of daybreak.” Both are accurate genitive constructions; the difference in their rhetorical fit should not be mistaken for a different syntactic rule.