Worthy Cause

The buyback clause is the part doing the design work here: a one-mana instant that sacrifices a creature for lifegain is a footnote, but a one-mana instant that can return to your hand turns sacrifice itself into a repeatable action. Pay the buyback and Worthy Cause stops being a spell and becomes an outlet, a sacrifice button you cast at instant speed and never lose. That window matters. Because the sacrifice happens as you cast it and the card resolves on the stack, you can answer removal by cashing in the creature on your own terms, banking the toughness as life rather than ceding it, then snapping the card back for the next loop. The lifegain is incidental flavor on what is functionally a reusable, in-color sacrifice outlet that costs no permanent slot on the battlefield. That is the trade Tempest's designers accepted: an outlet with no body to remove, no tapping, no summoning sickness, gated instead behind a recurring three-mana tax ( to cast plus for buyback each iteration) and the reality that you still have to keep finding creatures to feed it. It reads as a humble combat trick and behaves as engine plumbing, the kind of card whose ceiling lives entirely in what you sacrifice and what triggers when the creature leaves.