While diluting an acid, why is it recommended that the acid should be added to water and not water to the acid?

Explanation

Dilution of a concentrated acid , particularly concentrated sulphuric acid ,is a highly exothermic reaction . When water is added to a concentrated acid , the heat liberated is so large that the solution starts almost boiling .This may cause spriting of the hot acid solution and harm the person .Excessive local heating may even break the glass container .That is why concentrated acids are diluted by slowly adding concentrated acid into water with constant stirring and not by adding water to the acid .