Allah (Subhanahu wa taala) takes an Oath by the Ten Nights of Dhul-Hijjah/ Hajj and swearing an oath by something is indicative of its importance and great benefit: “I swear by the dawn, and by the Ten Nights”, [Q89:1] The last Prophet, Mohammed (Sallalahu Alaihi Wassallam) said: "Islam has been built on five [pillars]: testifying that there is no god but Allah and that Muhammed is the Messenger of Allah, performing the prayers, paying the zakat (Charity), making the pilgrimage to the House (Hajj), and fasting in Ramadan (Roza)." #Hajj