Islam is to testify that there is no god but Allah and that Muhammad is the Messenger of Allah, to establish prayer, to pay Zakah, to fast Ramadan, and to perform Hajj to the House if you are able to find a way thereto

'Umar ibn al-Khattāb (may Allah be pleased with him) informs that Jibrīl (peace be upon him) appeared before the Companions (may Allah be pleased with them) in the form of an unknown man with white clothes and very dark hair and the signs of travel - such as fatigue, dust, unkempt hair, and dirty clothing - were not visible on him. None of those present knew him. This happened while they were sitting with the Prophet (may Allah's peace and blessings be upon him). He sat down before the Prophet (may Allah's peace and blessings be upon him) as a learner and asked him about Islam. He answered him, pointing out the pillars of Islam: acknowledgment of the two testimonies of faith, observing the five prayers, paying the Zakah to its due recipients, fasting the month of Ramadan, and performing the obligation of Hajj for those who are able to do so.

The inquirer said: You have spoken the truth. The Companions wondered that he posed the question, which indicated that he apparently did not know the answer, and then he affirmed that the answer was right.

Then, he asked the Prophet (may Allah's peace and blessings be upon him) about faith, and he answered him listing the six pillars that contain belief in the existence of Allah Almighty and His attributes, ascribing His actions, such as creation, to Him alone, and devoting worship only to Him; belief that the angels, whom Allah created from light, are honorable servants who do not disobey Allah Almighty and they execute His commands; belief in the scriptures revealed by Allah Almighty to the messengers, like the Qur’an, the Torah, and the Gospel, and in the messengers who conveyed Allah's religion, such as Noah, Abraham, Moses, Jesus, and the last of them Muhammad (peace be upon all of them); belief in the Last Day, which includes the barzakh life (life after death in the grave) and that every human being will be resurrected after death and undergo the reckoning and will ultimately end up in Paradise or Hellfire; and belief that Allah had predestined all things according to His prior knowledge, wisdom, writing, and will, and that everything happens according to Allah's predestination and creation. Then, he asked him about ihsān, and the Prophet (may Allah's peace and blessings be upon him) told him that ihsān is to worship Allah as if you can see Him, and if he cannot reach that level, he should then worship Allah Almighty as if Allah is watching him. The first is the level of watching, which is higher, and the second is the level of watchfulness.

Then, he asked the Prophet (may Allah's peace and blessings be upon him) about the Hour, and he clarified that knowledge of the Hour is one of the things Allah kept to Himself alone; so, none of the creation knows it, neither the one inquired about it nor the inquirer.

Then, he asked him about the signs of the Hour. He pointed out that its signs include the increasing number of slave girls or the prevalence of children's ingratitude toward their mothers as they treat them like slaves and that shepherds and poor people will lead a life of opulence in the latter times, taking pride in the construction and decoration of big houses.

Then, the Prophet (may Allah's peace and blessings be upon him) informed that the inquirer was Jibrīl, who came to teach the Companions this upright religion.