March 17

The prescribed ablutions consist of washing the hands and the face in preparation for [obligatory] prayer. In the case of the medium Obligatory Prayer, this is accompanied by the recitation of certain verses.

That ablutions have a significance beyond washing may be seen from the fact that even should one have bathed oneself immediately before reciting the Obligatory Prayer, it would still be necessary to perform ablutions (Q and A 18). 
- The Universal House of Justice  (The ‘Notes’ section of the Kitab-i-Aqdas)