"And turn not your face away from men with pride, nor walk in insolence through the earth. Verily, Allah likes not any arrogant boaster." (Quran; Surah Luqman:18)
The Prophet saw (pbuh) said:
"The gates of Paradise will be opened on Mondays and on Thursdays, and every servant [of Allah] who associates nothing with Allah will be forgiven, except for the man who has a grudge against his brother. [About them] it will be said: ‘Delay these two until they are reconciled; delay these two until they are reconciled.'” [Muslim (also by Malik and Abu Dawud)]
“Beware of suspicion, for suspicion is the worst of false tales; and do not look for the others’ faults and do not spy, and do not be jealous of one another, and do not desert (cut your relation with) one another, and do not hate one another; and O Allah’s worshipers! Be brothers (as Allah has ordered you!)." (Bukhari)