Harm No. 1: Disobedience of Allah
Casting evil glances is clearly forbidden by the نص قطعی clear and explicit text of the Qur'aan. Allah Ta'ala says:
﴿ قل للمومنین یغضوا من ابصارھم ﴾
“O Nabi ﷺ Tell the believing men to lower some of their gazes." [Sura Nur ; Ayat 30, Juz 18]
(Meaning, do not look at ghair mahram women and handsome boys). Therefore, he who casts evil glances is opposing the clear and explicit command of Qur'aan, and one who opposes the clear and explicit command of Qur'aan is guilty of committing a HARAAM act. Thus, to save oneself from this sin, it is sufficient to meditate upon the fact that the one who casts evil glances is opposing a commandment of the Qur’aan. In other words, he is disobeying Allah Ta'ala.