Why do people say "God Bless You" after you sneeze?

People say "God Bless You" after you sneeze is a phrase dating back to
Biblical times. Back then, a sneeze was believed to be a sign of
imminent danger to the person who sneezed, most likely because a sneeze,
way back then, was a symptom commonly associated with the plague.

Therefore, when someone sneezed it was believed they were in need of
immediate help from God. And now you know where the saying "God Bless
You" when someone sneezed developed.