Cast Traveling Plague by paying 3, attaching it to another creature you control.
When Traveling Plague enters, Archon of Sun's Grace triggers, creating a creature token.
Activate Woe Strider by sacrificing the creature Traveling Plague is attached to.
When the creature dies, Traveling Plague triggers, returning itself from your graveyard to the battlefield attached to the token created in step 2.
When Traveling Plague enters, Archon of Sun's Grace triggers, creating a creature token.
Resolve the Woe Strider ability.
Repeat from step 3.
This mesmerizing loop is built upon the clever recursive property of Traveling Plague: whenever the creature it enchants leaves the battlefield, the Aura dutifully returns itself to the battlefield attached to a new target. By using Woe Strider to sacrifice the creature currently bearing the Plague, you immediately trigger that return clause, recycling the Aura right back onto the battlefield. Meanwhile, Archon of Sun's Grace watches each iteration with its constellation ability, translating every single re-entry of the enchantment into a fresh Pegasus token ready to be fed right back into Woe Strider's maw for endless scrying and sacrifices.