David, Covetous King

David cannot block while he has Sin.
Creatures with Sin cannot be specifically targeted
by their controller's spells. (Spells that affect all
of a player's creatures still affect it.)
{1}{p/b}{p/b}, {t}: David gains Sin. Gain control of
target creature for as long as David has sin on the battlefield. That creature cannot attack or block.
{w}{w}, {t}: David loses Sin and cannot activate it's abilities for the rest of the game. You gain 4 life.