Islam highly commends humbleness and simplicity and reckons that as one of the traits of a true believer. The Prophet 
said:
“Al-Kibr (proud and arrogance) is rejecting the truth and looking down upon people.”
[Muslim, At-Tirmithi and Abu Daawood]
Humility is for one who is important and significant and he fears to gain notoriety or to become too great among people. As it was said, “Humble yourself, you will be as a glimmering star to the viewer on the surface of the water even if it is lofty.” We don’t say to an ordinary person, “Humble yourself.” But it is said to him, “Know the value of yourself, and do not place it in the wrong place!”
It was narrated by Al-Khattaabi 
in Al-Uzlahthat Imaam `Abdullaah ibn Al-Mubaarak came to Khuraassaan [in Persia] and went to a person who was known for his Zuhd and Wara’ [asceticism and cautiousness in piety], so when he entered where the man was, he (the man) did not turn around nor give him any consideration at all.
in Al-Uzlahthat Imaam `Abdullaah ibn Al-Mubaarak came to Khuraassaan [in Persia] and went to a person who was known for his Zuhd and Wara’ [asceticism and cautiousness in piety], so when he entered where the man was, he (the man) did not turn around nor give him any consideration at all.When ‘Abdullaah Ibn Al-Mubaarak left, some of the people who were inside with the man said to him, “Don’t you know who he was?!“ He said, “No.” He was told, “This is the ‘Ameer of the believers…`Abdullaah Ibn Al-Mubaarak.” So the man was astonished and came out to ‘Abdullaah Ibn Al-Mubaarak in a hurry apologizing and absolving himself from what happened, saying, “O Abu ‘Abdur-Rahmaan! Forgive me and advise me!” Ibn Al-Mubaarak said, “Yes… whenever you come out of your house and see someone, assume that he is better than you!” He knew that the man was conceited. When ‘Abdullaah Ibn Al-Mubaarak inquired as to what the man’s profession was, he found out that he was a weaver!! Therefore, this educated Imaam noticed that this Mutazahhid (devoted pious person) possessed a kind of arrogance, conceitedness and feeling of superiority over others.
inquired as to what the man’s profession was, he found out that he was a weaver!! Therefore, this educated Imaam noticed that this Mutazahhid (devoted pious person) possessed a kind of arrogance, conceitedness and feeling of superiority over others.This disease sometimes envelops pious people; this is why he was offered advice that was easy for him. Many times we find this characteristic in some pious people, as well as some callers to Islam. But when it reaches the small students who misbehave with their scholars and teachers, this really hurts inside! There is no objection if you differ in opinion or judgment with a scholar as long as you are qualified to do so. The problem occurs when this difference of opinion becomes a destructive element to the scholar’s dignity, diminishes his value, disregards and disrespects him.
One should humble himself with his companions. Frequently when the spirit of competition and envy is agitated between companions and rivals, a person may feel superior over his companion, he may be pleased by harming him, degrading his value and importance, accusing him of defects or exaggerating his faults; faults that may have come to light when seeking advice, or correction. In reality this is called jealousy.
Humility is to humble oneself to one who is below you. If you find someone who is younger than you, or of less importance than you, you should not despise him, because he might have a better heart than you, or be less sinful, or closer to Allah than you. Even if you see a sinful person and you are righteous, do not act with arrogance towards him, and thank Allah that He saved you from the tribulation that He put him through. Remember that there might be some Riyaa’ (showing off) or vanity in your righteous deeds that may cause them to be of no avail, and that this sinful person may be regretful and fearful concerning his bad deeds, and this may be the cause of forgiveness of his sins.
According to Jundub, may Allah be pleased with him, the Messenger of Allah mentioned that a man said,
mentioned that a man said,“By Allah, Allah will not forgive so-and-so,” and that Allah said: “Who is swearing by Me that I will not forgive so-and-so? I surely have forgiven so-and-so and nullified your deeds.”
[Muslim].
Therefore, do not act in arrogantly towards anyone. Even when you see a sinner, do not show superiority towards him, nor treat him with arrogance and domination. If you feel that the sinner may perform some acts of obedience which you do not, and that you may also posses some defects which the sinner may not, then deal kindly with him, and gently give Da`wah which will hopefully be the cause of his acceptance and remembrance.
Your deeds also should not become too great in your eyes. If you do a good deed, or attempt to get closer to Allah through an act of obedience, your deed still may not be accepted. Allah Says what means:
“…Indeed, Allah only accepts from the righteous [who fear Him].”
(Quran 5:27)
This is why some ofthe Salaf (predecessors) said, “If I knew that Allah accepted one Tasbeeh (saying “Subhaanallaah”) from me, I would have wished to die right now!”
The arrogant person never gives credit to anybody or mentions good about someone, and if he needed to do so, he would also mention defects of that person. But if he hears somebody reminding him about his own defects, he will not be flexible nor comply due to his inferiority complex. This is why it is among man’s moral integrity to accept criticism or comment without any sensitivity or discomfort or feelings of shame and weakness. Here he is, the ‘Ameer of the Believers `Umar, may Allah be pleased with him, raising the flag and lifting the motto, “May Allah have mercy on a person who informed us of our defects.”