Narrated by Ibn Umar (RA): " Allah's Apostle said, Islam is based on the following five principles:
(1)to testify that none has the right to be worshipped but Allah and Muhammed is His Apostle.
(2) To perform the (compulsary congrgational) prayers dutifully and perfectly.
(3) To pay Zakat (i.e. obligatory charity).
(4) To observe fast during the month of Ramadhan
(5) To perform Hajj (i.e. Pilgramage to Mecca)
(Sahih Bukhari: Kitaab ul Imaan)
A man came to the Prophet SAW and said, ‘O Messenger of God! Who among the people is the most worthy of my good companionship? The Prophet SAW said: Your mother. The man said, ‘Then who?' The Prophet SAW said: Then your mother. The man further asked, ‘Then who?' The Prophet SAW said: Then your mother. The man asked again, ‘Then who?' The Prophet SAW said: Then your father. (Bukhari, Muslim).
"O you who believe! Avoid much suspicion, for some suspicions are a sin. Do not spy on one another, nor backbite one another. Would one of you love to eat the flesh of his dead brother? Nay, you would abhor it, [so similarly, avoid backbiting]. And fear Allah. Indeed, Allah is Most Forgiving, Most Merciful." Qur'an, [49:12]