The sin of Pride

Hadith - Bukhari's Book of Manners #550
Abu Huraira, r.a., reported that the Prophet of Allah, upon him be peace, said, "Whoever eats with his servant, or rides a donkey in the marketplace, or who ties up his goat and milks it will no be guilty of the sin of pride.

Hadith - Bukhari's Book of Manners #556, Abu Dawud and Tirmidhi
Abu Huraira, r.a., reported that a handsome man went to the Prophet of Allah, upon him be peace, and said, "I love beauty, and I have been given what you see, even to the extent of my hating to be bested. Is that pride?" The Prophet replied, "No. Rather, pride is to disdain the truth and to treat others with contempt."


The sin of flattering or praising a person

(Flattering or praising is not just to say something kind about a person. Praising is to glorify especially by the attribution of perfections. Flattering is to praise excessively especially from motives of self-interest.)

Hadith - Sahih Bukhari, Muslim, Abu Dawud, Tirmidhi, Ahmad, Abu 'Awanah, and Ibn Hibban.
Abu Bakr reported that a man was mentioned in the presence of the Prophet, saaws, and another praised the man. The Prophet, saaws, said, "Woe to you, for you have broken your friend's neck!" The Prophet saaws repeated this several times and then said, "If any of you simply must praise another, let him/her say, 'I think the person is this way or that...' if you genuinely think the person to be that way. The Final Reckoner is Allah, and no one can tell Allah anything about anyone."

Hadith - Bukhari's Book of Manners #337, Bayhaqi, and similar version by Ibn Majah.
Aslam reported that he heard 'Umar say, "Praise is slaughter." One of the narrators added, "That is, if you accept it."

Hadith - Bukhari's Book of Manners #338, Nasa'i, Tirmidhi, Ibn Hibban, and Hakim
Abu Huraira, r.a., reported that the Prophet of Allah, saaws, said, "What a fine man Abu Bakr is. What a fine man 'Umar is. What a fine man Abu 'Ubaydah is. What a fine man Usayd ibn Hudayr is. What a fine man Thabit ibn Hudayr is. What a fine man Mu'adh ibn 'Amr ibn al Jumuh is. What a fine man Mu'adh ibn Jabal is." He said, "What a foul man so and so is. What a foul man is so and so."

Hadith - Sahih Bukhari and Muslim
'A'ishah reported that a man requested an audience with the Prophet, saaws. The Prophet said, "What a foul tribesman that one is." But when the man entered, the Prophet was cordial and pleasant to him. When the man left, another asked permission to meet with him. The Prophet said, "What a good tribesman that one is." But when he entered, the Prophet was not nearly as cordial with him as he had been with the first. When he left, 'A'ishah asked, "You said what you did about the first man, yet you met him cordially. And you said what you did about the second one, and yet you were reserved with him." The Prophet said, "O 'A'ishah, the worst kind of people are those whose vulgarity must be avoided."