Allah's Messenger (ﷺ) said, "From among the portents of the Hour are (the following): -1. Religious knowledge will be taken away (by the death of Religious learned men). -2. (Religious) ignorance will prevail. -3. Drinking of Alcoholic drinks (will be very common). -4. There will be prevalence of open illegal sexual intercourse.
Sahih al-Bukhari Book 3, Hadith 22
← Previous Hadith The Prophet (ﷺ) said, "The example of guidance and knowledge with which Allah has sent me is like abundant rain falling on the earth, some of which was fertile soil that absorbed rain water and brought forth vegetation and grass in abundance. (And) another portion of it was hard and held the rain water and Allah benefited the people with it and they utilized it for drinking, making their animals drink from it and for irrigation of the land for cultivation. (And) a portion of it was barren which could neither hold the water nor bring forth vegetation (then that land gave no benefits). The first is the example of the person who comprehends Allah's religion and gets benefit (from the knowledge) which Allah has revealed through me (the Prophets and learns and then teaches others. The last example is that of a person who does not care for it and does not take Allah's guidance revealed through me (He is like that barren land.)"

Sahih al-Bukhari Book 3, Hadith 21 Next Hadith → I will narrate to you a Hadith and none other than I will tell you about after it. I heard Allah's Messenger (ﷺ) saying: From among the portents of the Hour are (the following): -1. Religious knowledge will decrease (by the death of religious learned men). -2. Religious ignorance will prevail. -3. There will be prevalence of open illegal sexual intercourse. -4. Women will increase in number and men will decrease in number so much so that fifty women will be looked after by one man.

Sahih al-Bukhari Book 3, Hadith 23