How To Bless

Why is there a mitzvah for kohanim to bless Yisroel, God can give us the beracha directly?  Why must the beracha be given b’ahavah, why is this condition so critical that it becomes part of the text of the beracha said before the pessukim of birchas kohanim?

Possibly, it is the very fact that another person, the kohanim are able to look at someone else favorably that causes that Hashem will also look favorably upon the recipient.  It is because the kohan expresses such love for another individual that it arouses such love in heaven for the individual as well.

The Gemorah in Chagigah (16b) says that Hashem didn’t learn the Torah of Rebbe Meyer since he learnt from Acher.  After Rabbah bar Shela explained that he merely studied the Torah of acher, not his actions, then Hashem said the Torah of Rebbe Meyer.  Did Hashem not know this beforehand?  It’s the same idea, because Rabbah bar Shela looked favorably upon the actions of Rebbe Meyer it caused that Hashem looked upon them favorably as well (see Tzidkus Hatzaddik of Rav Tzaddok #21.)