The dua when entering Mekke includes: 'Allahumma hadha haramuka wa amnuka, faharrimni 'alan-nar, wa ammini min 'adhabika yawma tab'athu 'ibadak, waj'alni min awliya'ika wa ahli ta'atik' — O Allah, this is Your sanctuary and security, so forbid me from the Fire, secure me from Your punishment on the Day You resurrect Your servants.
اللَّهُمَّ هَٰذَا حَرَمُكَ وَأَمْنُكَ، فَحَرِّمْنِي عَلَى النَّارِ، وَآمِنِّي مِنْ عَذَابِكَ يَوْمَ تَبْعَثُ عِبَادَكَ، وَاجْعَلْنِي مِنْ أَوْلِيَائِكَ وَأَهْلِ طَاعَتِكَ
Allahumma hadha haramuka wa amnuk, faharrimni 'alan-nar, wa ammini min 'adhabika yawma tab'athu 'ibadak, waj'alni min awliya'ika wa ahli ta'atik.
Meaning: O Allah, this is Your sanctuary and Your place of security, so forbid me from the Hellfire, secure me from Your punishment on the Day You resurrect Your servants, and make me among Your close allies and the people of Your obedience.
Source: Musnad Ahmad #3343Entering Mekke is entering the most sacred land on earth, the Haram established by Prophet Ibrahim (sallallahu aleyhi ve sellem). The dua draws a beautiful parallel between Mekke as a physical sanctuary of safety and seeking spiritual sanctuary from Allah's punishment. It is a moment of profound spiritual arrival that every haci should mark with sincere dua.
اللَّهُمَّ هَٰذَا حَرَمُكَ وَأَمْنُكَ، فَحَرِّمْنِي عَلَى النَّارِ، وَآمِنِّي مِنْ عَذَابِكَ يَوْمَ تَبْعَثُ عِبَادَكَ، وَاجْعَلْنِي مِنْ أَوْلِيَائِكَ وَأَهْلِ طَاعَتِكَ
It was the practice of the early Muslims to supplicate upon entering Makkah, connecting the physical sanctuary (haram) of Makkah with seeking sanctuary from the Hellfire.