Randomex is correct about his Shluchei Mitzvah Chiluk, I believe.
The Gemara says it’s impossible for a Shliach Mitzvah to be harmed, yet quotes a story that it did. The only answer is in the Olam HaEmes, not here.
There is, however, a difference between a Hezek that is solely Min Hashamayim and one that came through others utilizing their own Bechira, according to some Rishonim.