When Fiend Hunter enters, its first ability triggers, exiling Sister Hospitaller.
Activate Woe Strider by sacrificing Fiend Hunter.
When Fiend Hunter dies, its second ability triggers, returning Sister Hospitaller from exile to the battlefield.
When Sister Hospitaller enters, it triggers, returning Fiend Hunter from your graveyard to the battlefield.
When Fiend Hunter enters, its first ability triggers, exiling Sister Hospitaller.
Resolve the Woe Strider ability.
Repeat from step 3.
This elegant loop turns a modest resurrection engine into an endless cycle of sacrifices and returns. By using Woe Strider to feed Fiend Hunter to the graveyard, you trigger Sister Hospitaller's entry ability to pull the Hunter right back out, which in turn re-exiles the Hospitaller. The constant cycling through the battlefield and graveyard lets you feed Woe Strider's sacrifice outlet over and over, securing infinite death triggers, life gain, and infinite scry 1s to set up your next draw.