Belief

Bukhari :: Book 1 :: Volume 2 :: Hadith 41

Narrated 'Aisha:

Once the Prophet came while a woman was sitting with me. He said, "Who is she?" I replied, "She is so and so," and told him about her (excessive) praying. He said disapprovingly, "Do (good) deeds which is within your capacity (without being overtaxed) as Allah does not get tired (of giving rewards) but (surely) you will get tired and the best deed (act of Worship) in the sight of Allah is that which is done regularly."

Bukhari :: Book 1 :: Volume 2 :: Hadith 42

Narrated Anas:

The Prophet said, "Whoever said "None has the right to be worshipped but Allah and has in his heart good (faith) equal to the weight of a barley grain will be taken out of Hell. And whoever said: "None has the right to be worshipped but Allah and has in his heart good (faith) equal to the weight of a wheat grain will be taken out of Hell. And whoever said, "None has the right to be worshipped but Allah and has in his heart good (faith) equal to the weight of an atom will be taken out of Hell."

Bukhari :: Book 1 :: Volume 2 :: Hadith 43

Narrated 'Umar bin Al-Khattab:

Once a Jew said to me, "O the chief of believers! There is a verse in your Holy Book Which is read by all of you (Muslims), and had it been revealed to us, we would have taken that day (on which it was revealed as a day of celebration." 'Umar bin Al-Khattab asked, "Which is that verse?" The Jew replied, "This day I have perfected your religion For you, completed My favor upon you, And have chosen for you Islam as your religion." (5:3) 'Umar replied,"No doubt, we know when and where this verse was revealed to the Prophet. It was Friday and the Prophet was standing at 'Arafat (i.e. the Day of Hajj)"