Anas (Radiyallaahu `anhu) reported Allah’s Apostle (Sallallaahu `alayhi wa sallam) about the major sins. He (the Holy Prophet) observed:
“Associating anyone with Allah, disobedience to parents, killing a person and false utterance.”

Anas b. Malik (Radiyallaahu `anhu) reported Allah’s Messenger (Sallallaahu `alayhi wa sallam) said:
“Neither nurse mutual hatred, nor jealousy, nor enmity, and become as fellow brothers and servants of Allah. It is not lawful for a Muslim that he should keep his relations estranged with his brother beyond three days.”

Abu Hurairah (Radiyallaahu `anhu) reported Allah’s Messenger (Sallallaahu `alayhi wa sallam) said:
“The servant speaks words that he does not understand its repercussions but he sinks down in Hell-Fire farther than the distance between the east and the west.”

Narrated Jarir bin ‘Abdullah (Radiyallaahu `anhu) reported The Prophet (Sallallaahu `alayhi wa sallam) said:
“He who is not merciful to others, will not be treated mercifully.”

Abu Hurairah (Radiyallaahu `anhu) reported Allah’s Apostle (Sallallaahu `alayhi wa sallam) said:
“The Hour (last day) will not be established until (religious) knowledge will be taken away, earthquakes will be very frequent, time will pass quickly, afflictions will appear, murders will increase and money will overflow amongst you.”

Salim reported on the authority of his father (Radiyallaahu `anhum) that Allah’s Messenger (Sallallaahu `alayhi wa sallam) said:
“A Muslim is the brother of a fellow-Muslim. He should neither commit oppression upon him nor ruin him, and he who meets the need of a brother, Allah would meet big needs, and he who relieved a Muslim from hardship Allah would relieve him from the hardships to which he would be put on the Day of Resurrection, and he who did not expose (the follies of a Muslim) Allah would conceal his …

Abu Hurairah (Radiyallaahu `anhu) reported Allah’s last Messenger (Sallallaahu `alayhi wa sallam) said:
“Do you know what is backbiting?”
They (the Companions) said:
“Allah and His Messenger know best.”
Thereupon he (the Prophet) said:
“Backbiting implies your talking about your brother in a manner which he does not like.”
It was said to him:
“What is your opinion about this that if I actually find (that failing) in my brother which I made a mention of?”
He said:
“If (that failing) is actually found (in him) what you assert, you in fact backbited him, …

Abu Hurairah (Radiyallaahu `anhu) reported Allah’s Apostle (Sallallaahu `alayhi wa sallam) said:
“The servant (who conceals) the faults of others in this world, Allah would conceal his faults on the Day of Resurrection.”