Why must wudu be done to pray? According to Islam, if someone wants to be sanctified, he must take a bath and if he wants to pray, he must do wudu. Can it be explained scientifically? As a Muslim I know everything in Islam can be explained scientifically and none of those opposes the humanity. Wudu can sanctify us externally. But if air passes through back of one, then he became unsanctified for praying. Why? In this case just air passed. Then why we must do wudu. And if we do, what will be the impact?