Activate Woe Strider by sacrificing another creature.
When the creature dies, Bishop of Wings' second ability triggers, creating a 1/1 Spirit creature token.
When the Spirit token enters the battlefield as an Angel due to Xenograft, Bishop of Wings' first ability triggers, causing you to gain 4 life.
Resolve the Woe Strider ability.
Repeat.
This clever loop turns Woe Strider into an engine of continuous recycling by putting Xenograft to work, setting its type to Angel so that everything you field joins the heavenly host. That type-shifting is the linchpin that makes Bishop of Wings pay out twice: every token that hits the board nets you four life, and every time you feed that same token back to Woe Strider's sacrifice ability, the Bishop replaces it with a fresh Spirit to keep the cycle going. Together, these three cards create an endless loop of life gain and sacrifices that lets you scry through your entire deck at will.