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)
The Prophet (peace be upon him) said: “There has come to you the disease of the nations before you, jealousy and hatred. This is the ‘shaver’ (destroyer); I do not say that it shaves hair, but that it shaves (destroys) faith…” (Al-Tirmidhi, No. 2434)
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)
For more read here.