Is there a Diffrence?

is there a diffence in defensive spells and protecting agaisnt spells?

I dont catch what you mean. Explain.

Saves reduce the effectiveness of a spell. For instance, if you successfully save versus a hellstream, it'll do less damage... a mangle instead of a disintegrate, maybe. Saving against something like sleep makes it fail... the intended effect of the spell does not go through. A spell like sanctuary has no impact on how well you save against the spell, it's just a blanket reduction of all incoming damage. So you can save against that hellstream and make it a mangle, then have sanc cut that mangle down to a lacerate.