If a Muslim can't physically perform Hajj, they can ask someone to do it on their behalf as long as that person has done their own Hajj already.
This year, the Saudis have launched a "smart haj" initiative, with apps to help pilgrims with everything from travel plans to medical care. This is considered as the first pilgrimage in Islam.
Qatar has accused Saudi Arabia of blocking its citizens from attending this year's hajj because of the ongoing diplomatic feud.
All is now set for the commencement of the 2018 hajj rites in Saudi Arabia with about two million pilgrims from across the world including about 60 thousand from Nigeria.
Muslim pilgrims walk towards Namirah mosque on Arafat Mountain, during the annual hajj pilgrimage, outside the holy city of Mecca on Sunday.
"For many Muslims this is the big, the biggest, dream of life, to see Kaaba and pray for yourself and the whole Muslim nation".
Meanwhile, the custodian of the two sacred mosques of Makkah and Medina yesterday urged pilgrims to avoid the emerging congestion and crowd mounting on the holy cities, especially during congregation prayers.
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Every Muslim is required to complete the hajj at least once in their lifetime if they have the means to do so.
After prayers in Mecca, pilgrims will head to an area called Mount Arafat on Monday, where the Prophet Muhammad delivered his final sermon.
For those undertaking annual haj pilgrimage and reach the valley of Mount Arafat, it is the time for celebrations and feasting.
"Arafah is the Hajj and pilgrim that missed it has not fulfilled the fundamental pillar of the pilgrimage".
The oil-flush kingdom ended its ban on women driving in June and has boosted female employment in a male-dominated society.
Nayef Ahmed, 37, told Reuters that in order to afford the hajj he had to sell a plot of land in Yemen, which is embroiled in a three-year proxy war between Saudi Arabia and Iran.
They traditionally slaughter sheep for the three-day Eid al-Adha, a tribute to the prophet Abraham's sacrifice of a lamb after God spared Ishmael, his son.
One-third of all pilgrims live in Saudi Arabia but the remainder come from all over the world. Pilgrims will return to pray there at the end of haj.