There is no doubt that enabling women to mix with men is the basis of all calamity and evil, and it is one of the greatest causes of all-encompassing punishment coming down. It is also one of the causes of corruption in public and private affairs. Mixing of men and women is the cause of a great deal of immoral actions and zina. And it is one of the causes of widespread death and ongoing plagues.
One of the greatest causes of widespread death is the prevalence of zina, because of enabling women to mix with men and walk among them displaying their finery and beautified. If the people in charge knew how much corruption that causes in worldly affairs and people’s affairs, let alone religious affairs, they would be stricter in putting a stop to it.
Ibn Qayyim, Al-Turuq al-Hukmiyyah, p. 407-408