question #3 Sahih Muslim 16d, Book 1, Hadith 22 : Why is the performance of Hajj considered one of the essential pillars of Islam?

I heard the messenger of Allah (ﷺ) say: Verily, al-Islam is founded on five (pillars): testifying the fact that there is no god but Allah, establishment of prayer, payment of Zakat, fast of Ramadan and Pilgrimage to the House.