“Our Lord! And make us submissive unto You and of our offspring a nation submissive unto You, and show us our Manasik (all the ceremonies of pilgrimage – Hajj and Umrah, etc.), and accept our repentance. Truly, You are the One Who accepts repentance, the Most Merciful.” (Quran: 2/128)

Verily! As-Safa and Al-Marwah (two mountains in Makkah) are of the Symbols of Allah. So it is not a sin on him who performs Hajj or Umrah (pilgrimage) of the House (the Kabah at Makkah) to perform the going (Tawaf) between them (As-Safa and Al-Marwah). And whoever does good voluntarily, then verily, Allah is All-Recognizer, All-Knower. (Quran: 2/158)

And perform properly (i.e. all the ceremonies according to the ways of Prophet Muhammad (p.b.u.h.)), the Hajj and Umrah (i.e. the pilgrimage to Makkah) for Allah. (Quran: 2/196)
The Hajj (pilgrimage) is (in) the well-known (lunar year) months (i.e. the 10th month, the 11th month and the first ten days of the 12th month of the Islamic calendar, i.e. two months and ten days). So, whosoever intends to perform Hajj therein (by assuming Ihram), then he should not have (….. ) relations (with his wife), nor commit sin, nor dispute unjustly during the Hajj. And whatever good you do, (be sure) Allah knows it. And take a provision (with you) for the journey, but the best provision is At-Taqwa (piety, righteousness, etc.). So fear Me, O men of understanding! (Quran: 2/197)

There is no sin on you if you seek the Bounty of your Lord (during pilgrimage by trading, etc.). Then when you leave Arafat, remember Allah (by glorifying His Praises, i.e. prayers and invocations, etc.) at the Mashar-il-Haram. And remember Him (by invoking Allah for all good, etc.) as He has guided you, and verily, you were, before, of those who were astray. (Quran: 2/198)
And Hajj (pilgrimage to Makkah) to the House (Kabah) is a duty that mankind owes to Allah, those who can afford the expenses (for ones conveyance, provision and residence); and whoever disbelieves (i.e. denies Hajj (pilgrimage to Makkah), then he is a disbeliever of Allah), then Allah stands not in need of any of the Alameen (mankind and Jinns). (Quran: 3/97)

O you who believe! Kill not game while you are in a state of Ihram for Hajj or Umrah (pilgrimage), and whosoever of you kills it intentionally, the penalty is an offering, brought to the Kabah, of an eatable animal (i.e. sheep, goat, cow, etc.) equivalent to the one he killed, as adjudged by two just men among you; or, for expiation, he should feed poor persons, or its equivalent in fasting, that he may taste the heaviness (punishment) of his deed. Allah has forgiven what is past, but whosoever commits it again, Allah will take retribution from him. And Allah is All-Mighty, All-Able of Retribution. (Quran: 5/95)

Lawful to you is (the pursuit of) water game and its use for food – for the benefit of yourselves and those who travel, but forbidden is (the pursuit of) land game as long as you are in a state of Ihram (for Hajj or Umrah). And fear Allah to Whom you shall be gathered back. (Quran: 5/96)

Allah has made the Kabah, the Sacred House, an asylum of security and Hajj and Umrah (pilgrimage) for mankind, and also the Sacred Month and the animals of offerings and the garlanded (people or animals, etc. marked with the garlands on their necks made from the outer part of the stem of the Makkah trees for their security), that you may know that Allah has knowledge of all that is in the heavens and all that is in the earth, and that Allah is the All-Knower of each and everything. (Quran: 5/97)

And proclaim to mankind the Hajj (pilgrimage). They will come to you on foot and on every lean camel; they will come from every deep and distant (wide) mountain highway (to perform Hajj). (Quran: 22/27)

Allah Azza wa Jall mentioned the sacrifice together with the first and foremost worship in Islam: prayer. This is a clear indication of its great importance. Thus, He ordered His Messenger (p.b.u.h.) to slaughter sacrifices by saying: <<…Pray unto your Lord and slaughter (your sacrifice)…” (Quran: 109/2)