Shield of the Oversoul is a common Enchantment — Aura card from Shadowmoor (SHM), collector number 242. Current market price: $2.05 (foil $30.00), TCGplayer market prices via Scryfall.
Enchant creature As long as enchanted creature is green, it gets +1/+1 and has indestructible. (Damage and effects that say "destroy" don't destroy it. If its toughness is 0 or less, it still dies.) As long as enchanted creature is white, it gets +1/+1 and has flying.