I think this card could be good in principle, but this execution is weak. Too heavy-handed (and also way too cheap). Let's let it do this same stuff, but not so ultimately. Also, I'll give it some sweet flavor text.
Null Prophet

Creature -- Prophet
0/3
Null Prophet comes into play with three devotion counters on it.
When Null Prophet has no devotion counters on it, sacrifice it.

, remove a devotion counter from Null Prophet: Choose one -- counter target activated or triggered ability; or creatures target player controls can't attack this turn; or target player can't play spells this turn.
In the end, he practiced what he preached.I lowered the counters to 3 so that he could use each ability exactly once.