Indeed, the first House [of worship] established for mankind was that at Bakkah

Hajj is not a new institution introduced by Islam, rather it is as old as the Ka'bah itself. Allah Almighty Says (what means): "Indeed, the first House [of worship] established for mankind was that at Bakkah [i.e., Makkah] – blessed and a guidance to the worlds.” [Quran 3:96]