Anas ibn Malik (رضى الله عنه) said that when he was sitting with the Messenger of Allah (صلى الله عليه وسلم), he said: “Coming upon you now is a man from the people of Paradise.” So a man came from the Ansar whose beard looked disarrayed by the water from Wudu (ablution), and he was carrying both of his shoes with his left hand.

The next day the Prophet (صلى الله عليه وسلم) repeated the same words, and the Ansar came in the same condition.

The third day the Prophet repeated the same again, and the Ansar man showed up in the same condition.

When the Messenger of Allah (صلى الله عليه وسلم) stood up to leave, Abdullah ibn Umar ibn Al-’As followed the man and asked him, “I have quarreled with my father and I have sworn not to enter my home for three days. May I stay with you?” He said: “Yes.”

Abdullah ibn Umar ibn Al-‘As stayed three nights with him but never saw him praying at night, and whenever he went to bed, he would remember Allah and rest until he woke up for Fajr prayer.

Abdullah said that he never heard anything but good from his mouth. When three nights had passed and he did not see anything special about his actions, Abdullah asked him, “O servant of Allah! I have not quarreled with my father nor have I cut relations with him. I heard the Messenger of Allah (صلى الله عليه وسلم) say three times that a man from the people of Paradise was coming to us, and then you came. So I thought I should stay with you and see what you are doing that I should follow, but I did not see you do anything special. What is the reason that the Messenger of Allah spoke highly of you?”

The man said: “It is as you have seen.” When Abdullah was about to leave, the man said, “It is as you have seen, except that I do not find fraud in my soul towards the Muslims, and I do not envy anyone because of the good that Allah has given them.”

 
[Musnad Imam Ahmad, Narrations of Anas ibn Malik, Number 12286]

All humans are dead, except those who have knowledge.
And all those who have knowledge are asleep, except those who do good deeds.
And those who do good deeds are deceived, except those who are sincere.
And those who are sincere are always in a state of worry.

 
[Imam Shaafi`]

Ibn Abbas (radiyAllaahu 'anhu) reported: One day the Messenger of Allah (sallAllaahu 'alayhi wa sallam) ascended mount As-Safa and he called out, “O people! Come at once!”

So the Quraish gathered before him.

He (sallAllaahu 'alayhi wa sallam) said, “Indeed, I am ‘a warner to you before the coming of a severe punishment.’ [34:46] Do you think that if I told you that the enemy was preparing to attack you in the morning or evening you would believe?”

Abu Lahab said, “Is it for this that you have called us? May you perish!”

So Allah revealed the verse, “Perish the hand of Abu Lahab!” [111:1].

 
[Sunan At-Tirmidhi, Book 44, Number 3363, Sahih]

Say: If your fathers, your sons, your brothers, your wives, your kindred, the wealth that you have gained, the commerce in which you fear a decline, and the dwellings in which you delight … are dearer to you than Allah and His Messenger, and striving hard and fighting in His Cause, then wait until Allah brings about His Decision (torment). And Allah guides not the people who are Al-Fasiqun (the rebellious, disobedient to Allah).

 
[Qur'an (9):24]

Uqbah ibn Amir (radiyAllaahu 'anhu) narrated the Prophet (sallAllaahu 'alayhi wa sallam) said:

“Whoever sees a fault and conceals it is like the one who brought back to life an infant girl who had been buried alive.”

 
[Sunan Abu Dawud, Book 40, Number 4891]