Perhaps I read surahs for my protection that day…since I usually do that. It could be their effect and Allah’s mercy in warding the dog away from me.
I once read a story this guy had posted on a website about how him and his friend were being followed by a huge dog (I think it was black). The boy asked his friend to recite the ayatul kursi but he didn’t know it, so his friend recited something else. The boy himself began reciting the Ayatul Kursi and he noticed a strange thing happen. The dog stopped following the boys…but it kept barking and moving back and forth as if it were being attacked by some invisible force. This invisible distraction…helped the boys to get away. Pretty freaky eh?