You can use your shield to reflect some of a spell’s power back at your enemies.

You must be wielding a shield to use this ability.

When a blast spell misses you,
or you pass a save against a blast spell,
you may direct that spell’s effect at a new target.

(You still suffer any consequences of passing the save.)
(This does not count as you casting the spell.)
(Spells without a duration which only deal damage are blast spells. Monster spells which fit this description but are not explicitly tagged as such should be considered blast spells.)