Arthur Malcolm Stace, known as Mr Eternity, was an Australian soldier. He was an alcoholic from his teenage years until the early 1930s, when he converted to Christianity and began to spread his message by inscribing the word "Eternity" in copperplate writing with yellow chalk on footpaths and doorsteps in and around Sydney, from Martin Place to Parramatta, from 1932 to his death in 1967. He has become somewhat of a legend in the local folklore of the city, and the story of his life has inspired books, museum exhibits, statues, an opera, and a film.

The word Eternity was a graffito tag recorded over an approximate 35-year period from 1932 to 1967, written numerous times in chalk in the streets of Sydney, Australia. The word had been written by Arthur Stace, an illiterate former soldier, petty criminal and alcoholic who became a devout Christian in the late 1940s.