Malachi translates from Hebrew as "my messenger," a title rather than a personal name in its earliest biblical use, later adopted as a given name in its own right. It carries connotations of delivering something important -- a voice entrusted with a message rather than speaking only for itself.
The Moon in ruminating signs joined to retrograde planets, it is not then good to purge; the potion will work upward to the patients injury. - William Lilly (1602.-1681.)