Hadith about Belief.

Bukhari :: Book 1 :: Volume 2 :: Hadith 15

Narrated Anas:

The Prophet said, "Whoever possesses the following three qualities will have the sweetness (delight) of faith:

1. The one to whom Allah and His Apostle becomes dearer than anything else.

2. Who loves a person and he loves him only for Allah's sake.

3. Who hates to revert to Atheism (disbelief) as he hates to be thrown into the fire."

Bukhari :: Book 1 :: Volume 2 :: Hadith 16

Narrated Anas:

The Prophet said, "Love for the Ansar is a sign of faith and hatred for the Ansar is a sign of hypocrisy."

Bukhari :: Book 1 :: Volume 2 :: Hadith 17

Narrated 'Ubada bin As-Samit:

who took part in the battle of Badr and was a Naqib (a person heading a group of six persons), on the night of Al-'Aqaba pledge: Allah's Apostle said while a group of his companions were around him, "Swear allegiance to me for:

1. Not to join anything in worship along with Allah.

2. Not to steal.

3. Not to commit illegal sexual intercourse.

4. Not to kill your children.

5. Not to accuse an innocent person (to spread such an accusation among people).

6. Not to be disobedient (when ordered) to do good deed."

The Prophet added: "Whoever among you fulfills his pledge will be rewarded by Allah. And whoever indulges in any one of them (except the ascription of partners to Allah) and gets the punishment in this world, that punishment will be an expiation for that sin. And if one indulges in any of them, and Allah conceals his sin, it is up to Him to forgive or punish him (in the Hereafter)." 'Ubada bin As-Samit added: "So we swore allegiance for these." (points to Allah's Apostle)