By: Muhammad Ayaz
The Prophet صلی اللہ علیہ وسلم said: "If you hear of an outbreak of plague in a land, do not enter it; but if the plague breaks out in a place while you are in it, do not leave that place." (Reported by al-Bukhari and Muslim.)
Modern science now understands the ways in which microorganisms multiply and the diseases they cause. Scientists affirm that healthy people who have no symptoms in the place of plague are already carrying the microbe and so they represent a real threat because they may transfer the plague to another place if they move to it.
Thus, this system of quarantine, in which all the people of the city that suffers from plague are prevented from leaving, and visitors are also prevented from entering, has now been established worldwide. In the 15th century, plague hit Europe causing the death of a quarter of its citizens. At that time, plagues and contagious diseases were much less in the Muslim world.
Rasulullah صلی اللہ علیہ وسلم established the system of quarantine which is considered the basis of modern preventative medicine. He ordered his Companions: "If you hear of an outbreak of plague in a land, do not enter it; but if the plague breaks out in a place while you are in it, do not leave that place." In order to make sure that his order would be carried out properly, he صلی اللہ علیہ وسلم established a wall around the area of the plague and promised those who are patient and stay in the area of the plague with the reward of the martyrs, and those who run away from it were promised doom and perdition. Thus, he said: "He who runs away from the place of the plague is like the one running away from fighting in the cause of Allah and he who forbears it and stays where he is, he will be rewarded with the reward of a martyr."
It was later discovered that those who appear to be healthy with no symptoms, are the germ carriers who might transfer the plague to another place if they moved to it. They would move freely and mingle with healthy people, and cause them to catch the disease.