Hajj revolves around Tawheed and ‘Ibaadah.
Muslims, from Prophet Adam, (pbuh) to the end of time, belong to a single fraternity (ummah). They are bound together by the concept of Tawheed (Monotheism). In Hajj, this concept of Tawheed-based solidarity is translated into deeds as Muslims from a wide range of backgrounds stand united in one place, worshipping one god, undivided by race, color, language or nationality. The Qur'an taught in many verses that all human beings descend from a single ancestor, that none has an intrinsic right of superiority over another, whatever one's race, nation, or social standing.
Ibadah or acts of worship differ as to how many times a Muslim is required to do them. Some ibadat are required once a year, like the fasting of the month of Ramadhan; some are due once a week such as Salatul Jumuah (Friday Salah); others are demanded on a daily basis such as the five daily salahs; and some are mandatory once in a lifetime such as Hajj.
To Allah we belong and to Him is our return. [Quran 2:156]. All affairs tend toward Allah. Our goal is not to "perish", but to "bloom". This is done not "for Allah" but rather to bring us "toward Him". Allah is not so far away from you; therefore, try to reach Him! Allah is closer to you than yourself! The Way of Allah, to Whom belongs whatever is in the heavens and whatever is on earth. Behold (how) all affairs tend towards Allah. (Quran 42:53) .. We are nearer to him than his jugular vein. (Quran 5:16)