By: Aishah Ahmed
“[Of these stories mention] When Joseph said to his father, “O my father, indeed I have seen [in a dream] eleven stars and the sun and the moon; I saw them prostrating to me. He said, “O my son, do not relate your vision to your brothers or they will contrive against you a plan. Indeed Satan, to man, is a manifest enemy.” [Surah Yusuf, 12: 4,5]
Ibn Katheer in his explanation of this ayah says, “….Ya`qub feared that if Yusuf narrated his vision to any of his brothers, they wouldenvy him and conspire evil plots against him.” 
Yes, brothers and sisters in Islam, the evil eye is true. The Prophet said:
“The evil eye is real, and if anything were to overtake the divine decree (al-qadar) it would be the evil eye.” 
This is a trait that Allah mentions in the Qur’an and our Prophet has warned us about:
‘The disease of previous nations has crawled its way to you: envy and hatred.’ 
What is Evil Eye?
The Arabic word al-‘ayn (translated as the evil eye) refers to when a person harms another with his eye.  Its counterpart is hasad(jealousy), which is the hoping in the removal of the blessing from the one who is envied.
Simply put, when one sees his brother blessed with what Allah has given him, he hopes that his blessing disappears from him for no reason except for his envy towards him.