Hajj or pilgrimage to Mecca is one of the five pil
The Holy Prophet sent off 300 Muslims under the leadership of Hazrat Abubakr Siddique (may Allah be pleased with him) to Mecca so that they could perform Hajj. That was the year when it was banned for the Mushrikeen (those who associate partners with Allah) to enter Ka’ba. It was also made unlawful to perform Tawaaf (circling of Ka’ba) with naked body.
 
The following year, 10th Hijra, the Holy Prophet (peace be upon him) announced a head of time he himself would perform Hajj that year.
He led tens of thousands of Muslims to Hajj that year and demonstrated to Muslims how to perform all the rites and rituals of the Hajj.
This Hajj is known in history as Hajjatul Wida’ or Farewell Pilgrimage because this proved to be the last Hajj the Holy Prophet (peace be upon him) performed. At the end of this farewell pilgrimage, the divine revelation that had started some 22 years ago came to an end with the following verse of Surah Al-Maidah

“This day have I completed My commandments for you, and have brought to its fullness the favor that I have bestowed upon you, and have chosen Islam as your religion”

Hajj is an act of worship just like Salat (five daily prayers) and Sawm (fasting in the month of Ramadan). Muslims from all over the world gather in Mecca in the last month of Muslim calendar and worship Allah. Hajj is a special worship that lasts for several days. This is an occasion that brings Muslims of all countries, colors, and races to one place – the Ka’ba. This is a unique opportunity of worshipping Allah collectively in a large gathering at one place.