What is the ruling on a Muslim man accidentally seeing women's 'awrah in public places, and is it considered a sin if he is unable to control his gaze despite his attempts to lower it?

An accidental glance is excused if one's gaze falls upon a woman unintentionally and is immediately averted. This is supported by the hadith: "I asked the Messenger of Allah, peace and blessings be upon him, about an accidental glance? He commanded me to avert my gaze."

However, if one prolongs the gaze, he sins, based on the words of Allah Almighty: (Tell the believing men to lower their gaze) and the words of the Prophet, peace and blessings be upon him: "O Ali, do not follow one glance with another, for the first is yours but the last is not." One of the greatest means of lowering the gaze is marriage.