Imaan (Faith) & Islam (Self-Submission)
Both of these were answered by Prophet Muhammad ﷺ when two men approached him on two different occasions.
A prophetic hadith informs us that: One day while Allah's Messenger ﷺ was sitting with the people, a man came to him walking and said, "O Allah's Messenger ﷺ what is Imaan (Faith)?" Allah’s Messenger ﷺ said, "Faith is to believe in Allah, His Angels, His Books, His Apostles (Messengers), and the meeting with Him, and to believe in the Resurrection." In another narration, he also added “…and that you believe in qadr (divine decree or predestination) in its entire entirety.” The Quran also confirms these articles as part of Islamic faith: “The Messenger has believed in what was revealed to him from his Lord, and [so have] the believers. All of them have believed in Allah and His angels and His books and His messengers, [saying], "We make no distinction between any of His messengers.”
In a prophetic hadith we are informed : A man from Najd with unkempt hair came to Allah’s Messenger ﷺ and we heard his loud voice but could not understand what he was saying, until he came near and then we came to know that he was asking about Islam. Allah’s Messenger ﷺ said, “You have to offer prayers perfectly 5 times in a day and night (twenty-four hours).” The man asked, “Is there any more (praying)?” Allah’s Messenger ﷺ replied, “No, but if you want to do voluntary (nawafil) prayers (you can).” Allah’s Messenger ﷺ further said to him: “You have to observe fasts during the month of Ramadan.” The man asked, “Is there any more fasting?” Allah’s Messenger ﷺ replied, “No, but if you want to observe the voluntary (nawafil) fasts (you can).” Then Allah’s Messenger ﷺ further said to him, “You have to pay the zakat (obligatory charity).” The man asked, “Is there anything other than the zakat for me to pay?” Allah’s Messenger ﷺ replied, “No, unless you want to give additional charity of your own.” And then that man retreated saying, “By God! I will neither do less nor more than this.” Allah’s Messenger ﷺ said, “If what he said is true, then he will be successful (i.e. he will be granted Paradise)”. In another hadith the Prophet kept it short but added all five pillars: “al-Islam is raised on five (pillars), testifying (the fact) that there is no god but Allah, that Muhammad is His servant and messenger, and the establishment of salah (5 times prayer), payment of zakat (obligatory charity), pilgrimage (hajj & umrah) to the house (kaabah) and the fast of ramadan.”
All five actions called the five pillars of Islam as taught in hadith and mentioned in the Quran, constitute as deen (way of life) of Islam. The seven articles of faith mentioned in the Quran and the hadith constitute as what we call Imaan (faith) and majority of Islamic scholars accept this view. Various topics related to faith such as Allah ﷻ and His existence, His attributes and communication with us, Islamic concept of worship, angels and jinns (invisible beings), Day of Judgment, prophethood and revelation, are all further discussed in this website.
 Sahih Bukhari - Book 2, Hadith 43
 Sahih Muslim – Hadith 10
 Al Quran 2:285
 Sahih Al-Bukhari, Kitab Al-Iman, Hadith no. 44
 Sahih Muslim Hadith 16
 The Arabic term deen means ‘way of life’ usually translated as 'religion'.