Piety

Toughness-only combat tricks that fire on defense occupy a strange corner of white's early design: they win the combat math without ever shifting the initiative back to your side of the table. The restriction here is sharper than the rate. The bonus applies only to blocking creatures, which means it cannot push damage through on the attack, cannot pump a creature you control while it is the aggressor, and cannot be used proactively at all. It is a pure defensive reaction: the opponent has to commit to the attack, and you have to be willing to declare blockers first. What it does well, it does at instant speed. Plus-three toughness across every blocker can ambush a midrange attacker, blank a pile of small creatures, or sneak a blocking creature out from under a burn spell like Lightning Bolt during the combat step. The multiplicative angle is where it earns its slot, since the bonus hits all your blockers at once: throw two or three small bodies in front of one big attacker and a single spell can survive the block while killing the attacker, turning a losing trade into a clean swing in your favor. Pinning the effect to the blocker's side looks like a deliberate brake on early aggression in a set where combat math was still being calibrated; white got the defensive tool, but only when playing defense. Later white instants found better rates by folding in lifegain, prevention, or a buff that worked on either side of combat. This one is locked to the blocker's side, and that lock is what dates it.