Tap two untapped Clerics you control: Prevent all damage target creature would deal this turn.
Tap two untapped Wizards you control: Prevent all damage target spell would deal this turn.
If the ability is activated targeting a spell that becomes a permanent, it also prevents any damage from that permanent this turn.
It can tap itself but is not required to do so.
Since the ability does not have the {T} symbol, you can use the ability before this creature begins a turn under your control.