‘Umar Ibn Al-Khattab (may Allah be pleased with him) narrated: “Once while we were sitting with the Messenger of Allah ﷺ, a man dressed in pure white clothes, with very black hair, without any sign of travel, and whom none of us recognized, appeared before us. He sat with the Messenger of Allah ﷺ. He rested his knees against the knees of the Messenger of Allah ﷺ, placed his palms on the thighs of the Messenger of Allah ﷺ, and said:
‘O Muhammad, inform me about Islam.’ The Messenger of Allah ﷺ said:
‘Islam is to testify that there is no god worthy of worship but Allah and that Muhammad is the messenger of Allah, to establish the prayer, to pay Zakah (the obligatory charity), to fast the month of Ramadan, and to perform pilgrimage to Makkah if you are capable of it.’
The man said: ‘You have said the truth.’ ‘Umar said: We wondered at him, asking him and then confirming it as the truth!
Then the man said: ‘Then inform me about faith (Iman).’ The Messenger of Allah ﷺ said:
‘It [Iman] is to believe truly in Allah, in His angels, in His Books, in His messengers, in the Hereafter, and to believe truly in the Divine Decree, the good of it and the bad of it.’
The man said: ‘You have said the truth. Then inform me about Ihsan.’ The Messenger of Allah ﷺ said:
‘It [Ihsan] is to worship Allah as if you are seeing Him, for though you do not see Him, He, verily, sees you.’
The man said: ‘Then Inform me about the Hour (of the Day of Judgment).’ The Messenger of Allah ﷺ said: ‘The one questioned knows no more than the questioner.’ The man said: ‘Tell me some of its indications and signs.’ The Messenger of Allah ﷺ said: ‘They are that the slave-girl will give birth to her mistress and master, and that you will find barefooted, destitute goat-herders vying with one another in the construction of lofty buildings.’
‘Umar said: Then the man went on his way and I stayed with the Messenger of Allah ﷺ for a long while. The Messenger of Allah ﷺ then said to me: ‘O ‘Umar, do you know who the questioner was?’ I replied: Allah and His Messenger know best.’ He said: ‘That was the Angel Gabriel, who came to you in order to instruct you in matters of your religion.’ ” (Muslim, Abu Dawud,Tirmidhi, Al-Nisa’i, Ibn Majah, and Ahmad).
THE scholar Al-Baghawi said: “The Prophet ﷺ defined Islam as a term that describes outer good deeds, and he defined Iman as a term that describes inner beliefs.”
Imam al-Nawawi said: “The scholar Abu ‘Amr Ibn As-Salah said: ‘This hadith states the origin of Iman, and that is inner affirmation and belief; and it states the origin of Islam, and that is outer surrender and submission to Allah. Islam is determined and judged by the outer testimony that there is no god worthy of worship except Allah and that Muhammad is His Messenger. But the Prophet ﷺ added into the [basic] definition of Islam the five daily prayers, Zakah, Hajj, and fasting of Ramadan because these are the most apparent and greatest rituals of Islam. Thus, complete surrender is achieved by their performance, while leaving them makes submission incomplete or deficient.’”
Al-Mubarakpuri said in his book Mir’at al-Mafatih (a commentary on Mishkat al-Masabih): “The coming of this man happened at the end of the Prophet’s life ﷺ, as indicated by the narration of Ibn Mandah in the Book of Faith. So this event took place after the revelation of all the rulings of Islam that had been conveyed at different times, to state and summarize the essential points of Islam in one setting to ensure they are preserved and retained.”
Qadi ‘Iyad said: “This hadith contains all the kinds of outer and inner forms of worship, including the conditions of Faith (Iman), outer good deeds performed by the limbs, sincerity of the inner self, and the avoidance of major sins; therefore, all religious knowledge is based on this hadith and branches out from it.”