A major difference between the sin of lustful evil glances and other sins is the fact that, upon committing any other sin, the effect of that sin after it is committed ends and the heart becomes satisfied. But casting lustful evil glances is such a sin that the more one commits it, the more intense the desire to repeat the sin. One’s eating and drinking is limited. Sooner or later one will not be able to eat an additional morsel, or take an additional sip. One’s hunger and thirst will be satisfied but the lustful evil glance is such a calamity that one is never satiated.Considering this feature of evil lustful glances, it is more detrimental than most other sins.

Taken from a lecture entitled Ghadh-ul-Basr by Hakeem-ul-Ummah Maulana Ashraf Ali Thanwi (RA)