البَلَدِ

A word in the Arabic language will either be 1) a verb or 2) a noun or 3) a particle – البَلَدِ is a noun

A noun may either be 1) Definite or indefinite 2) Masculine or feminine 3) Singular, dual or plural 4) Nominative, accusative or genitive

البَلَدُ is the natural state of this definite noun and it changes to البَلَدِ due to: 1) a preposition that precedes it or 2) a possessed noun that precedes it or 3) it’s a noun of dependent declension a) نَعْتٌ / صِفَطٌ adjectives b) التَّوْكِيْدُ emphatic c) المَعْطُوْفٌ conjunction d) البَدَلُ synonym

Land, City

To settle, remain in, occupy (a country)

Verse/Below are the 3 verses in the holy Quran containing the genitive nounالبَلَدِ
Ayat
90-1Nay, I swear by this city (Mecca)لَآ أُقْسِمُ بِهَذَا الْبَلَدِ
90-2and you are free in this cityوَأَنْتَ حِلٌّ بِهَذَا الْبَلَدِ
95-3and this secure cityوَهَذَا البَلَدِ الأَمِيْنِ