This is a glorious statement by the Beloved and Blessed Prophet صَلَّى اللهُ تَعَالٰى عَلَيْهِ وَاٰلِهٖ وَسَلَّم: If a Muslim looks once at the beauty of a woman (unintentionally) and then lowers his eyes, Allah عَزَّوَجَلَّ will grant him such a worship that he will feel its pleasure.
(Musnad Imām Aḥmad Bin Ḥanbal, vol. 8, pp. 299, Ḥadīš 22341)
The Noblest Prophet صَلَّى اللهُ تَعَالٰى عَلَيْهِ وَاٰلِهٖ وَسَلَّم stated that a Ḥadīš-e-Qudsī states: Looking is one of the poison-tipped arrows of the devil; if someone avoids it whilst fearing Me, then I will grant him such faith (Īmān) that he shall feel its sweetness in his heart.
(Al-Mu’jam-ul-Kabīr liṭ-Ṭabarānī, vol. 10, pp. 173, Ḥadīš 10362)
Eyes filled with fire
Ḥujjat-ul-Islam Sayyidunā Imām Muhammad Bin Muhammad Ghazālī عَـلَـیۡـهِ رَحْـمَـةُ الـلّٰـهِ الۡـوَالِی narrated, ‘Whoever fills his eyes with something Ḥarām, his eyes will be filled with fire on Judgement Day.’
(Mukāshafa-tul-Qulūb, pp.10)
Sayyidunā ‘Allāmaĥ Abul Faraj ‘Abdur Raḥmān Bin Jawzī عَـلَيْهِ رَحْـمَةُ الـلّٰـهِ الۡـقَـوِی reports, ‘Looking at a woman’s beauty is one of the poison-tipped arrows of the devil, whoever does not protect his eyes from a non-Maḥram, a needle of fire will be passed through his eyes on Judgement Day.’ (Baḥr-ud-Dumū’, pp. 171)
Ḥujjat-ul-Islam Sayyidunā Imām Muhammad Bin Muhammad Ghazālī عَـلَـیۡـهِ رَحْـمَـةُ الـلّٰـهِ الۡـوَالِی said: A man who cannot shut his eyes cannot protect his private parts either.