(Wudhu). This is the ritual ablution that all Muslims perform before entering the prayer and is unique to Islam. The literal meaning of the word ('Wu-dhu') is 'to turn on the light'. This 'turning on the light' is the first step to entering the room. The Holy Prophet said "On the Day of Resurrection, my followers will be known from the traces of ablution and whoever can increase the area of his radiance should do so". By performing the ablution in the proper manner, one increases his radiance and illumination (Dhu'), thus becoming 'light upon light'.