His statement, “Hajj and Umrah are obligatory”: it appears to me that the author did not intend to explain their ruling in itself, since that is clear: Hajj is one of the pillars of Islam. Rather, he intended to qualify this obligation by mentioning its conditions, saying, “They are obligatory upon the free Muslim,” as though someone were asking: Upon whom are Hajj and Umrah obligatory?
UPON THE FREE, LEGALLY RESPONSIBLE, AND ABLE MUSLIM, ONCE IN HIS LIFETIME, TO BE PERFORMED WITHOUT DELAY ..........
His statement, “upon the Muslim”: this is one of the conditions for Hajj and Umrah to be obligatory. Indeed, all acts of worship are obligatory only upon a Muslim, because an act of worship is not valid from a disbeliever, due to Allah’s saying, Most High:
“And nothing prevented their expenditures from being accepted from them except that they disbelieved in Allah and His Messenger.” [Quran 9:54]
Thus, Islam is a condition for every act of worship. When we say that it is not obligatory upon the disbeliever, this does not mean that he will not be punished for it. Rather, he is not commanded to perform it while in his disbelief, nor to make it up after accepting Islam. Thus, there are three matters:
First: the command to perform it.
Second: the command to make it up.
Third: sin.
The command to perform it is not addressed to the disbeliever, nor, if he accepts Islam, do we address to him the command to make it up. Yet the sin remains established: he will be punished for neglecting it, as well as for neglecting all the other branches of Islam.
His statement, “the free”: its opposite is the wholly enslaved person and the partially emancipated slave. This is the second condition for Hajj and Umrah to be obligatory: freedom. Therefore, Hajj is not obligatory upon a wholly enslaved person or one who is partially emancipated, because neither possesses any wealth. As for the wholly enslaved person, this is because his property belongs to his master, due to the Prophet’s saying, peace and blessings be upon him: “Whoever sells a slave who possesses property”