Oathbound Resolve

At the beginning of your upkeep, if you control no creatures with vow counters, return target creature card from your graveyard to the battlefield with a vow counter on it.

Creatures you control with vow counters on them have "Whenever this creature attacks, you gain life equal to your devotion to white." and "If this creature would leave the battlefield, exile it instead."

"For the truly faithful, death merely delays destiny."