No rest for the weary is a modification of the idiomatic phrase No rest for the wicked.
“No rest for the weary” is used to express that even in one is feeling exhausted and run down, they must persevere and keep on working.
No rest for the wicked comes from the Bible, first appearing in print in English during the 16th century, serving as the foundation for the titular expression.
Although the exact origin of the modification is not known, “No rest for the weary” was first published in print in English in 1744, in “The Roman History by Titus Livius with the Entire Supplement of John Freinsheim”.
“No rest for the weary” gained prominence in the subsequent centuries, appearing in various contexts over the 18th, 19th and 20th centuries, including literature, drama, newspapers as well as television series and movies.
The expression also became popular in poetry and music, serving as the title for several songs, by countless artists, including the 2013 song of Oathbreaker, or the 2008 track of Blue Scholars, just to name a few.