Abu Hurairah reported,

One day the Messenger of Allah ﷺ was sitting out in the open among the people when a man came to him and questioned him about a number of things. Among them, he asked, "Messenger of Allah, when will the Hour come?"The Prophet ﷺ replied, "The one asked about it knows no more than the one asking. But I will tell you about its signs. When a slave woman gives birth to her master, that is one of its signs. When the naked and barefoot become the leaders of the people, that is one of its signs. When the shepherds of sheep compete in raising tall buildings, that is one of its signs. It is among five things that none knows but Allah."Then he ﷺ recited, "Indeed, Allah alone has knowledge of the Hour. He sends down the rain, and He knows what is in the wombs. No soul knows what it will earn tomorrow, and no soul knows in what land it will die. Indeed, Allah is Aleem, All-Aware" [Luqman 31:34].The narrator said, "Then the man turned to leave, and the Messenger of Allah ﷺ said, 'Bring the man back to me.' They went to bring him back, but they could see nothing."The Messenger of Allah ﷺ then said, "That was Jibreel. He came to teach the people their religion."

عن أبي هريرة قال

كان رسول الله ﷺ يوما بارزا للناس، فأتاه رجل، فسأله عن أشياء منها: قال: يا رسول الله متى الساعة؟ قال: ما المسؤول عنها بأعلم من السائل، ولكن سأحدثك عن أشراطها، إذا ولدت الأمة ربها، فذاك من أشراطها، وإذا كانت العراة الحفاة رؤوس الناس، فذاك من أشراطها، وإذا تطاول رعاء البهم في البنيان، فذاك من أشراطها، في خمس لا يعلمهن إلا الله، ثم تلا ﷺ {إن الله عنده علم الساعة وينزل الغيث ويعلم ما في الأرحام وما تدري نفس ماذا تكسب غدا وما تدري نفس بأي أرض تموت إن الله عليم خبير} [سورة لقمان: آية ٣٤]. قال: ثم أدبر الرجل، فقال رسول الله ﷺ: ردوا علي الرجل، فأخذوا ليردوه فلم يروا شيئا، فقال رسول الله ﷺ: هذا جبريل جاء ليعلم الناس دينهم.