This two mana artifact enters tapped, it doesnt untap on your untap step, and at the start of your turn you can choose to skip your turn, untapping the Time Vault
The ability to phase any number of other creatures means that Guardian of Faith is good against spot removal and sweepers alike, and while it has a body that will generally trade in combat the flash threat more than makes up for this
Paired with Dawn of Hope, Archivist of Oghma can be twice as practical thanks to gaining you life
These are here primarily to blink Eluge, the Shoreless Sea, giving us an extra flood counter and speeding up our mana advantage, but also protecting Eluge from targeted removal (Teferi's Time Twist provides protection from board wipes too)
Its ability easily combines with several other cards to strip opponents hands, and keep them empty