Allah (swt) points out to Makkah, the secure city, which Allah (swt) has made it secure in response to Ibrahim’s (pbuh) supplication:

{إِذْ قَالَ إِبْرَاهِيمُ رَبِّ اجْعَلْ هَٰذَا بَلَدًا آمِنًا }

(And [mention] when Abraham said, “My Lord, make this a secure city…) (Al-Baqara: 126)

Allah (swt) here swears by four things: By two trees (the fig and the olive) and by two places: (Mount Sinai) – where Allah (swt) talked to Musa (pbuh)- and (the secure city) – Makkah that Allah (swt) made it a place for His sacred house and for the revelation upon the prophet Muhammad (saws).