I asked the Messenger of Allah (may Allah's peace and blessings be upon him) about the sudden glance, and he commanded me to avert my gaze

Jarīr ibn ‘Abdullāh (may Allah be pleased with him) asked the Prophet (may Allah's peace and blessings be upon him) about a man suddenly and unintentionally looking at an unrelated woman. In response, the Prophet (may Allah's peace and blessings be upon him) ordered him to turn his face to the other side once he knows it, and there is no sin on him.

1. The Hadīth urges to lower the gaze.
2. It warns against continuing to look at what is forbidden if one's sight falls on it suddenly and unintentionally.
3. It indicates that the prohibition of looking at women is an established matter among the Companions, as evidenced by the fact that Jarīr (may Allah be pleased with him) asked the Prophet (may Allah's peace and blessings be upon him): If he looked at a woman unintentionally, would his ruling be the same as the ruling of someone who looked intentionally?
4. It shows how Shariah cares about the interests of people, as it forbade men from looking at women due to the resultant evils in this world and the Hereafter.
5. The Companions used to refer to the Prophet (may Allah's peace and blessings be upon him) and ask him about things unclear to them. Likewise, ordinary Muslims should refer to their scholars and ask them about what is unclear to them.

صحيح مسلم (3/ 1699) (2159). نزهة المتقين، لمجموعة من الباحثين (2/ 1117). بهجة الناظرين، لسليم الهلالي (3/ 145). شرح رياض الصالحين، لابن عثيمين (6/ 362).