The Holy Quran and Sunnah
But the Prophet (A.S) left among you the same which other Prophets(A.S) left among their peoples because Prophets(A.S) do not leave them intended (in the dark) without a clear path and a standing ensign, namely the Book of your Creator, clarifying its permission and prohibitions, its obligations and discretion, its repealing injunctions and the repealed ones, its permissible matters and compulsory ones, its particulars and the general ones, its lessons and illustrations , its long and short ones , its clear and obscure ones, detailing its abbreviations and clarifying its obscurities.
In it, there are some verses whose knowledge1 is obligatory and others whose ignorance by the people is permissible. It also contains , what appears to be obligatory according to the Book 2 but its repeal is signified by the Prophet’s(A.S) action (sunnah) or that which appears compulsory according to the Prophet’s (A.S) action but the Book allows not following it. Or, there are those which are obligatory in a given time but not so after that time. Its prohibitions also differ. Some are major, regarding which there exists the threat of fire (Hell) and others are minor, for which there are prospects of forgiveness. There are also those of which a small portion is also acceptable (to Allah SWT) but they are capable of being expanded.
In this very sermon, he spoke about Hajj
Allah SWT has made obligatory upon you the pilgrimage (hajj) to His Sacred House which is the turning point for the people who go to it as beasts or pigeons go towards spring water . Allah SWT ,the Glorified, made it a sign of their supplication before His Greatness and their acknowledgement of His Dignity. He selected from among His creation , those who, on listening to His call, responded to it and testified His Word. They stood in the position of His Prophets(A.S) and resembled His angels who surround the Divine Throne , securing all the benefits of performing His worship and hastening towards His promised forgiveness. Allah SWT , the Glorified, made it (His Sacred House) an emblem for Islam and an object of respect for those who turn to it. He made obligatory its pilgrimage and laid down its claim for which He held you responsible to discharge it. Thus, Allah SWT, the Glorified, said:
..(Purely) for Allah, is incumbent upon mankind, the pilgrimage to the House, for those who can afford to journey thither. And whoever denieth , then verily, Allah is Self-sufficiently independent of the worlds( Quran: 3:97)
Translation by Yusuf Ali:
Pilgrimage thereto is a duty men owe to Allah, - those who can afford the journey; but if any deny faith, Allah stands not in need of any of His creatures.