Sahih Bukhari, Chapter: Knowledge

I will narrate to you a Hadith and none other than I will tell you about after it. I heard Allah's Apostle 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.