Praise be to Allah.
Sincerity (ikhlaas) is a necessary condition in all acts of worship, and no act of worship is valid if anything or anyone is associated with Allah. Allah says (interpretation of the meaning):
“So whoever hopes for the Meeting with his Lord, let him work righteousness and associate none as a partner in the worship of his Lord” [al-Kahf 18:110]
“And they were commanded not, but that they should worship Allah, and worship none but Him Alone (abstaining from ascribing partners to Him), and perform As‑Salaah (Iqaamat‑as‑Salaah) and give Zakaah, and that is the right religion” [al-Bayyinah 98: 5]
“So worship Allah (Alone) by doing religious deeds sincerely for Allah’s sake only.
3. Surely, the religion (i.e. the worship and the obedience) is for Allah only” [al-Zumar 39:2-3]
According to a saheeh hadeeth qudsi, the Prophet (peace and blessings of Allah be upon him) said: “Allah, may He be blessed and exalted, says: ‘I am so self-sufficient that I am in no need of having an associate. Thus he who does an action for someone else’s sake as well as Mine will have that action renounced by Me to him whom he associated with Me.’”
What is meant by sincerity towards Allah in worship is that nothing motivates the person to do that act of worship except love and veneration for Allah, and the hope for His reward and pleasure. Hence Allah says of Muhammad the Messenger of Allah (peace and blessings of Allah be upon him):
“Muhammad is the Messenger of Allah. And those who are with him are severe against disbelievers, and merciful among themselves. You see them bowing and falling down prostrate (in prayer), seeking Bounty from Allah and (His) Good Pleasure”
[al-Fath 48:29 – interpretation of the meaning]
No act of worship, whether it is Hajj or anything else, will be accepted if a person is doing it to show off to other people, or he is doing it so that other people will see him and say, “How pious So and so is, how much he worships Allah” and so on.
No worship will be accepted if the motivation behind it is to see places or see people, or other such things that are contrary to sincerity. Hence the pilgrims who go to the Sacred House must make their intention sincerely for the sake of Allah and not make it their intention to see the Muslim world, or to do business, or so that it will be said that So and so goes for Hajj every year, and so on.
There is nothing wrong with a person seeking the bounty of Allah by doing business whilst travelling to the Sacred House, because Allah says (interpretation of the meaning):
“There is no sin on you if you seek the Bounty of your Lord (during pilgrimage by trading)” [al-Baqarah 2:198]
What goes against sincerity is when a person’s only intention is to business and earn money. This is a person who seeks worldly gain by doing actions that have to do with the Hereafter. This means that the act of worship is invalid or that it is sorely lacking. Allah says (interpretation of the meaning):
“Whosoever desires (by his deeds) the reward of the Hereafter, We give him increase in his reward, and whosoever desires the reward of this world (by his deeds), We give him thereof (what is decreed for him), and he has no portion in the Hereafter” [al-Shoora 42:20]