An action with this trait requires a degree of mental concentration and discipline.
Spellshape
Actions with the spellshape trait tweak the properties of your spells. You must use a spellshape action directly before casting the spell you want to alter. If you use any action (including free actions and reactions) other than casting a spell directly after, you waste the benefits of the spellshape action. Any additional effects added by a spellshape action are part of the spell's effect, not of the spellshape action itself.
Source: Player Core pg. 119
Your faith provides temporary protection in addition to healing. If the next action you use is to cast harm or heal on a single target and the target regains Hit Points from the spell, it also gains a +2 status bonus to AC and saving throws for 1 round.