The unrestrained glance results in the one who looks becoming attracted to what he sees, and in the imprinting of an image of what he sees in his heart. This can result in several kinds of corruption in the heart of the servant. The following are a number of them:

It has been related that the Prophet(Sallallahu alayhi wa sallam) once said: The glance is a poisoned arrow of shaytan.

Whoever lowers his gaze for Allah, He will bestow upon him a refreshing sweetness, which he will find in his heart on the day he meets Him.

Shaytan enters with the glance, for he travels with it, faster than the wind blowing through an empty place. He makes what is seen appear more beautiful than it really is, and transforms it into an idol for the heart to worship. Then he promises it false rewards, lights the fire of desires within it, and fuels it with the wood of forbidden actions, which the servant would not have committed had it not been for this distorted image…

This distracts the heart and makes it forget its more important concerns. It stands between it and them, and so the heart loses its straight path and falls into the pit of desire and ignorance.

Allah  [Mighty and Glorious is He] says: Do not let your eyes look beyond them, desiring the luxuries of this worldly life. And do not obey those whose hearts We have made heedless of Our remembrance, who follow ˹only˺ their desires and whose state is ˹total˺ loss. [Source:- ‘Quran’ ~Surah al-Kahf: Ayah # 28]

The unrestrained gaze causes all three [3]afflictions. It has been said that between the eye and the heart is
an immediate connection. if the eyes are corrupted, then the heart follows. It becomes like a rubbish heap where all the dirt and filth and rottenness collect, and so there is no room for love for Allah, relating all matters to Him, awareness of being in His presence, and feeling joy at His proximity – only the opposite of these things can inhabit such a heart.

Staring and gazing without restraint is disobedience to Allah!

‘Tell the believing men to lower their gaze and guard their modesty; that is more purifying for them. Surely Allah is aware of what they do. [Source:- Quran ~Surah an-Nur: Ayah # 30]

Only the one who obeys Allah’s commands is content in this world, and only the servant who obeys Allah will survive in the next world. Letting the gaze run loose also makes the heart blind to distinguishing between truth and falsehood, between the sunnah and innovation: while lowering it for Allah [the Mighty and Exalted] gives it a penetrating, true, and distinguishing insight.

A righteous man once said: Whoever enriches his outward behavior by following the sunnah, and makes his inward soul wealthy through contemplation, and averts his gaze away from looking at what is forbidden, and avoids anything of a doubtful nature, and feeds solely on what is halal, his inner sight will never falter.

Rewards for actions come in kind. Whoever lowers his gaze from what Allah has forbidden, Allah will give his inner sight abundant reward  [Source:- Ibn al Qayyim al Jawziyya]