Hasad (jealousy and envy) is among the most destructive emotions which a man may develop toward his fellow human being. With Hasad, a person will wish evil for others and will be happy when misfortune befalls them. The Prophet (peace be upon him) warned against envy by comparing it to fire that completely burns the wood. He (peace be upon him) said: "Beware of jealousy, for verily it destroys good deeds the way fire destroys wood." (Abu Dawood)
Hasad can take a person into disbelief because he may conclude that Allah has not been fair with him, while Allah is the Most Just.
The person may forget all of Allah's mercy and blessings bestowed upon him. The Messenger of Allah (peace be upon him) said: "They are enemies of Allah's bounties." When asked, "Who are they?", he replied: "Those who envy people for what Allah has given them of Bounty." (At-Tabarani)
Allah through His Absolute Wisdom gave some people more wealth, intelligence, beauty, strength, and children than others. Discontentment comes from the slave's ignorance of his Lord. If he recognizes his Lord with the attributes of Perfection, he would not be discontent and as a result would not develop Hasad. A believing Muslim should be content with what Allah has destined for him. Imam Ibn Qayyim said: "It (contentment) opens the door of peace and security for the slave.
"Allah favored some of you over others with wealth and properties- Do they deny the favors of Allah?" (Qur'an, 16:71)
"Do they envy men for what Allah has given them of His Bounty?" (Qur'an, 4:54)
"It is We Who portion out between them their livelihood in this world, and We raised some of them above others in ranks, so that some may employ others in their work. But the mercy of your Lord is better." (Qur'an, 43:32)
his means that the mercy of Allah is better than the convenience of the world. Material things of this life do not make one superior over another. True superiority lies in Taqwa (righteousness and fear of Allah).
Allah said: "Surely, the most noble of you to Allah is the most God-fearing. "(Qur'an, 49:13)
"And the Hereafter with Your Lord is (only) for those who have Taqwa."(Qur'an, 43:35)
What belongs to the transient world is of no significance at all before Allah.
In order to discourage envy, the Prophet (peace be upon him) said: "Do not look to those above you. Look to those below you, as it will more likely remind you of Allah's favors bestowed on you." (Al-Bukhari and Muslim)
What Islam permits in contrast to Hasad (destructive jealousy) is Ghibtah (envy that is free from malice). It means that a person neither wishes for misfortune to fall on others nor does he hate the blessings with them. He desires for similar blessings without having any ill-feeling toward others.
The Messenger of Allah (peace be upon him) said: "Envy is allowed in two cases: a man whom Allah has given the Qur'an and who recites it throughout night and day; and a man on whom Allah has bestowed wealth who gives it away night and day." (Al-Bukhari and Muslim)
The Prophet (peace be upon him) also explained what is allowed to be said: "I wish I were given what he was given and did with it what he did."
The Messenger of Allah (peace be upon him) said: "The similitude of the people of this Ummah is like that of four individuals. One whom Allah has given wealth and knowledge, so he handles his wealth with knowledge.
One whom Allah has given knowledge but not wealth, and he says, 'Lord, should I have wealth like so-and-so, I would have handled it like him.' So they both have the same reward. Such a person loves to have wealth like others so he can do good like others without wishing that others lose their wealth.
"Another man whom Allah gave wealth but no knowledge spends it in disobedience to Allah. And last, a man whom Allah has not given knowledge or wealth but who says, 'Should I have wealth like so-and-so, I would spend it in the way he does.' So, both will have the same sin against them." (Al-Tirmidhi and Ibn Majah)