Casting Time: 1 bonus action
Range: 60 feet
Components: V, S, M (a small parchment with a bit of holy text written on it)
Duration: Concentration, up to 10 minutes
A shimmering field appears and surrounds a creature of your choice within range, granting it a +2 bonus to AC for the duration.
You can find more information on this spell in: PHB.275