When Felidar Guardian enters the battlefield, it triggers, targeting Vesperlark.
Holding priority, activate Woe Strider by sacrificing Felidar Guardian.
Resolve the Felidar Guardian trigger, blinking Vesperlark.
When Vesperlark leaves the battlefield, it triggers, returning Felidar Guardian from your graveyard to the battlefield.
Repeat from step 2.
This clever loop spins into motion when Felidar Guardian enters the battlefield and targets Vesperlark with its blink trigger, allowing Woe Strider to sacrifice Felidar Guardian in response. Because Felidar Guardian leaves play, it trips Vesperlark's leaves-the-battlefield trigger, which easily plucks the low-power Felidar Guardian right back out of the graveyard since its power is 1 or less. Meanwhile, Woe Strider happily fuels your engine by providing a steady stream of sacrifice outlets and infinite scry triggers to sculpt your draws.