Gavel of the Righteous

At the beginning of combat on your turn, put a charge counter on Gavel of the Righteous.

Equipped creature gets +1/+1 for each counter on Gavel of the Righteous.
As long as Gavel of the Righteous has four or more counters on it, equipped creature has double strike.

Equip {3}, or remove a counter from Gavel of the Righteous.