Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.001.

Allah, the Exalted One, says: “The first House (of worship) appointed for men was that at Bakka; (Bakka is one of the names of Makkah) full of blessings and guidance for all kinds of beings: in it are signs manifest (for example), the station of Abraham – whoever enters it attains security; pilgrimage thereto is a duty men owe to Allah–those who can afford the journey; but if any deny faith, Allah stands not in need of any of His creatures” (Qur’an 3.96-97).