According to Abu Hurayrah, the Prophet PBUH once asked his listners if they knew what slander was, to which they replied that God and His Messenger knew better. The Prophet PBUH then explained that slander meant speaking of one's brother in a manner that was hurtful to him. He ws then asked, what if one's brother was actually at fault. The Prophet PBUH replied that, if he was at fault, then what was said against him was just backbiting and, if he was not, it was calumny.

HADITH OF MUSLIM
On the Authority of Abu Hurayrah

'On the Day of Judgement, you will discover the worst man to be the one who had two faces.'

HADITH OF ABL-BUKHARI AND MUSLIM
On the Authority of Abu Hurayrah

'Abdullah said that it was not proper to tell lies either in serious or in light vein. Neither was it proper to make promises to one's children and then not fulfill them.

Al-Adab Al-Mufrad by Iman Al-Bukhari

'There are four charactaristics which together make a person a complete hypocrite.

The taint of hypocrisy will attach to the trustee who breaks his trust,
to the speaker who tells untruths,
to the maker of promises who fails to keep them and
to the man who uses foul language when in disagreement with others.

This taint will remain unless the wrongdoer mends his ways.'

HADITH OF AL-BUKHARI AND MUSLIM
On the Authority of 'Abdullah Ibn 'Amr Ibn Al-'As

'When three men travel together, they should make one of them their leader.'

HADITH OF ABU DAWUD
On the Authority of Abu Sa'id 'Al-Khudri

'Do not quarrel with your brother.
Do not ridicule him.
You should refrain from making a promise and then going back on it.'

HADITH OF AT-TIRMIDHI
On the Authority of Abdullah Ibn Al-'Abbas

'A man who helps his people for an unjust cause can be compared with a man, who catches hold of the tail of a camel which is falling into a well.'

HADITH OF ABU DAWUD
On the Authority of 'Abdullah Ibn Mas'ud

'It is ruinous for a man to tell lies so that others may laugh.
It is ruinous for him.
It is ruinous for him.'

HADITH OF AT-TIRMIDHI
On the Authority of Bahz Ibn Hakim

'Do not rejoice in the misfortunes of your brother. For God may show him compassion, but create difficulties for you.'

HADITH OF AT-TIRMIDHI
On the Authority of Wathilah

'The most perfect believers, in point of faith, is he who is the best in manners.'

HADITH OF ABU DAWUD
On the Authority of Abu Hurayrah

'Even if a group of people in a jungle number only three, it is still incumbent upon them to choose a leader.'

HADITH OF ABU DAWUD
On the Authority of 'Abdullah Ibn 'Amr

'None of you (truly) believes, until he wishes for his brother what he wishes for himself.'
HADITH OF BUKHARI
On the Authority of Anas Ibn Malik

PS: A very common hadith but rarely practised.

'Calling God in personal prayer is worship.'

HADITH OF ABU DAWUD AND AT-TIRMIDHI
On the Authority of Nu'man Ibn Bashir

'O God, only You can change our hearts. We beseech You to do so, so that we may submit to You.'

HADITH OF MUSLIM
On the Authority of 'Abdullah Ibn 'Amr Ibn Al-'As

According to Abu Bakr as-Siddiq, when he asked the Prophet PBUH to tell him of some invocations which he could recite in his prayers, the Prophet PBUH said,

'Say, God, I have been an oppressor to myself. And there is no one but You who can forgive my sins. Therefore forgive me in Your generosity. And show me compassion. Verily, You are Forgiving and Compassionate.'

HADITH OF AT-TIRMIDHI AND MUSLIM

According to Mu'adh, the Prophet PBUH took his hand in his own and said, 'O Mu'adh, by God, I love You.' Then he said, 'I give you this counsel: after each prayer, you must not omit to say,

"O God, help me to remember You, and thank You, and worship You with devotion."'

HADITH OF ABU DAWUD AND AN-NASA'I

"Abusing a Muslim is Fusuq (an evil doing) and killing him is Kufr (disbelief)."

- The Sahih Bukhari Hadeeth

Abu Hurayra said that the Messenger of Allah, may Allah bless him and grant him peace, said,

"Our Lord, the Blessed and Exalted, descends every night to the heaven of this world when the last third of the night is still to come and says, 'Who will call on Me so that I may answer him? Who will ask Me so that I may give him? Who will ask forgiveness of Me so that I may forgive him?' "

- A Imam Mailk's Muwatta Hadeeth

Al-Bara' b. 'Azib reported that Allah's Messenger (in may peace be upon him) commanded a person (in these words):

"When you go to bed during night, you should say:

' O Allah, I surrender myself to Thee and entrust my affair to Thee, with hope in Thee and fear of Thee. There is no resort and no deliverer (from hardship but Thou). I affirm my faith in the Book which Thou revealed and in the Messengers whom Thou sent.'

If you die in this state you would die on Fitra (Islam) "