What is the evidance of hajj? When was hajj made obligatory in islam?
The origins of pilgrimage are based on the Prophet Ibrahim’s practices, as he and his son Ismāʿil (as) built the Baytullāh and started the performance of pilgrimage for the first time. In the following verses, the following is stated about the beginning of the pilgrimage:
“Behold! We gave the site, to Abraham, of the (Sacred) House, (saying): ‘Associate not anything (in worship) with Me; and sanctify My House for those who compass it round, or stand up, or bow, or prostrate themselves (therein in prayer).’”
“And proclaim the Pilgrimage among men: they will come to thee on foot and (mounted) on every kind of camel, lean on account of journeys through deep and distant mountain highways”
“That they may witness the benefits (provided) for them, and celebrate the name of Allah, through the Days appointed, over the cattle which He has provided for them (for sacrifice): then eat ye thereof and feed the distressed ones in want. Then let them complete the rites prescribed for them, perform their vows, and (again) circumambulate the Ancient House.”
Until the city of Mecca was conquered in 630 CE by the Muslim army, the Kaʿba was full of idols and was visited by the polytheists in their own way. In this regard, the first verse in this regard “And complete the Hajj or ʿumra in the service of Allah”, which was revealed in the 6th year of the Hijra, commanded the completion of the Hajj and ʿumra that had already begun. As a matter of fact, that year, the Messenger of Allah, together with about 1400 Companions, entered the state of iḥrām for ʿumra and came to Hudaybiya, but when the Meccan polytheists did not allow them to perform ʿumra, they returned by signing the “Hudaybiya Treaty”. According to this treaty, the following year, this ʿumra that was left incomplete was made up.
According to the sound view, the pilgrimage in Islam was first made obligatory in the 9th year of Hijrah. The evidence on which this view is based is the following verse, “Pilgrimage thereto is a duty that men owe to Allah, those who can afford the journey.” That year, the Prophet appointed Abu Bakr (ra) the emir of pilgrimage, but he did not himself participate in the pilgrimage. The Farewell pilgrimage that he performed in the tenth year of Hijrah is the only pilgrimage he performed.
The following is stated in the hadiths:
“(The superstructure of) al-Islam is raised on five (pillars), i.e. Allah (alone) should be worshipped, and (all other gods) beside Him should be (categorically) denied. Establishment of prayer, the payment of zakāt, the Pilgrimage to the House, and the fast of Ramadan (are the other obligatory acts besides the belief in the oneness of Allah and denial of all other gods).”
When the above-mentioned verse, which states that hajj is obligatory, was revealed, the Messenger of Allah (saw) addressed his companions and said, “Allah, the Mighty and Sublime, has enjoined upon you Hajj.” A man said, “Every year?” The Prophet (saw) remained silent until he repeated it three times. Then he said, “If I said yes, it would be obligatory, and if it were obligatory you would not be able to do it. Leave me alone so long as I have left you alone. Those who came before you were destroyed because they asked too many questions and differed from their prophets. If I command you to do something then follow it as much as you can, and if I forbid you to do something then avoid it.” 
In a narration from Ibn Abbas (ra), it is stated that the one who asked the question was Aqraʿ ibn Ḥābis, and the following addition is included, “Whoever performs more than one pilgrimage, it will be a supererogatory pilgrimage.” This hadith shows that it is not necessary to repeat the hajj as farḍ. Muslim jurists agree that hajj is not obligatory more than once and that performing more than one hajj is considered supererogatory.
In another hadith, the following is stated, “Alternate between Hajj and ʿumra; for those two remove poverty and sins just as the bellows remove filth from iron, gold, and silver – and there is no reward for al-Hajj al-Mabrūr except for Paradise.”
In some cases, it may be necessary to perform more than one pilgrimage. That is to perform a votive pilgrimage and to make up an invalidated supererogatory pilgrimage. Sometimes, performing hajj becomes ḥaram like performing pilgrimage with ḥaram money. Sometimes it becomes makrūḥ, such as performing pilgrimage without the permission of parents who needs looking after. Moreover, it is makrūḥ for a debtor or a guarantor, who does not have any other property to pay his debt, to perform Hajj without the permission of the creditors. According to the Ḥanafis, this is a reprehensibility close to ḥaram.
According to the Ḥanafis, the Shafiʿis, and the Malikis, the pilgrimage performed with ḥaram money is valid even though it is a bad deed. These three schools have compared such a pilgrimage to the prayer performed on usurped land. Even though such a pilgrimage’s reward and virtue are reduced, the responsibility to perform obligatory or supererogatory pilgrimage is relinquished from that person. However, according to the Ḥanbalis, the hajj performed with ḥaram money is not valid since this school does not consider the prayer to be performed on usurped land valid, either.
Is Hajj Required to be Performed Immediately or can it be Performed Later in Life
According to Abu Ḥanīfah, Abu Yusuf, Imam Malik, and Aḥmad Ibn Ḥanbal, a pilgrimage is an act of worship that needs to be performed immediately. In other words, a believer who fulfills the necessary conditions must perform this worship in the first coming pilgrimage season. If he delays the pilgrimage to the following years, he becomes a sinner and his testimony in court will not be accepted. This is because delaying the pilgrimage is one of the minor sins, and insisting on it for years leads to committing a major sin. If such a person becomes poor before performing a pilgrimage, it is hoped that he will receive divine forgiveness if he borrows money and performs the pilgrimage. As the verses about the pilgrimage indicate that the pilgrimage should be performed without delay, the following hadiths also support it, “Whoever intends to perform Hajj, let him hasten to do so, for he may fall sick, lose his mount, or be faced with some need.” “Let a person die as a Jew or a Christian if he does not perform the pilgrimage without the hindrance of illness, urgent need, distress, or a sultan who oppresses the faith.”
According to the Shafiʿis and Imam Muhammad, hajj can be performed later in life (tarākhī). In other words, the one who meets the necessary conditions for pilgrimage does not have to perform this worship in the first coming pilgrimage season. However, it is Sunnah for such a person to perform Hajj or ʿumra without delay. For performing deeds that are considered obedience without delay and hastening in good deeds are among the characteristics that Islam recommends. It is commanded in a verse, “…then strive together (as in a race) Towards all that is good…” A person for whom the pilgrimage is obligatory may delay it to another year for reasons such as building a home, marrying his children, or even for no reason since although Hajj was made obligatory in the 9th year of Hijrah, the Prophet delayed it to the 10th year without any excuse. If it were not permissible to delay it, he would not have delayed it. This view is more appropriate as it will provide convenience to Muslims. For, besides the fact that the hadiths on which the majority of Islamic jurists are based do not give any definite orders, it is known that hajj was made obligatory in the 9th year of the Hijra and that the Messenger of Allah performed the pilgrimage in the 10th year of the Hijra.
 Al-Ḥajj, 22: 26-29.
 Al-Baqara, 2: 196.
 Āl ʿImrān, 3: 97.
 Al-Bukhari, Imān, 1, 2; Muslim, Imān, 19-22; al-Tirmidhī, Imān, 3; al-Nasā’ī, Imān, 13.
 Muslim, Ḥajj, 412; al-Nasā’ī, Manāsik, 1; Aḥmad ibn Ḥanbal, II, 508.
 Ibn Ḥanbal, II, 508; al-Nasā’ī, Manāsik, I; al-Shawkanī, ibid, IV, 279.
 Ibn al-Humām, Fatḥ al-Qadīr, Cairo 1316, II, 122; al-Shawkanī, ibid, IV, 280.
 Al-Tirmidhī, Ḥajj, 2; al-Nasā’ī, Ḥajj, 6; Ibn Maja, Manāsik, 3.
 Al-Kasanī, Badāyiʿ al-Ṣanā’iʿ, II, 223; al-Zuhaylī, ibid, III, 223.
 Abū Dawūd, Manāsik, 5; Ibn Maja, Manāsik, 1; Ibn Ḥanbal, I, 214, 225.
 Al-Shawkanī, ibid, IV, 284.
 Al-Baqara, 2: 148.
 Al-Shīrāzī, Muhadhdhab, I, 199; al-Zuhaylī, ibid, III, 17, 18.