The Quran

وَكَذٰلِكَ أَوحَينا إِلَيكَ قُرآنًا عَرَبِيًّا لِتُنذِرَ أُمَّ القُرىٰ وَمَن حَولَها وَتُنذِرَ يَومَ الجَمعِ لا رَيبَ فيهِ ۚ فَريقٌ فِي الجَنَّةِ وَفَريقٌ فِي السَّعيرِ

Muhammad Asad

[Thou art but entrusted with Our message:] and so We have revealed unto thee a discourse in the Arabic tongue¹ in order that thou mayest warn the foremost of all cities and all who dwell around it² - to wit, warn [them] of the Day of the Gathering, [the coming of] which is beyond all doubt: [the Day when] some shall find themselves in paradise, and some in the blazing flame.

Cf; 14:4 - "never have We sent forth any apostle otherwise than [with a message] in his own people's tongue": see also note 72 on the first sentence of 13:37.
I.e., all mankind (Tabari, Baghawi, Razi). As regards the designation of Mecca as "the foremost of all cities", see note 75 on the identical phrase in 6:92.