American boxer Muhammad Ali's rare collection of sketches and paintings will be going up for auction in New York next week. The 24-piece collection is a reflection of the legendary boxer's interest in religion and social justice. It is reported that Ali loved to hone his skills as an artist between his fights.

Mostly, the collection of the paintings are made in cartoon style and some of them are signed. There are also items that picture him in the ring.

"Ref, he did float like a butterfly and sting like a bee!" read the speech bubble from a boxer knocked out by an opponent with his arms raised in victory.

This painting is called "Sting Like a Bee". It was made by Ali in 1978 during the filming of the historical mini-series "Freedom Road", news agency Reuters reported. Ali featured in the mini-series, as well. Bonhams auctioneers said that it is expected that the auction will fetch around $40,000 – $60,000 at the sale on October 5.

Bonhams said, "Ali’s passion for drawing was little known, but he liked to sketch as a way of unwinding after a fight or training."

A lot of people are excited because no one knew he was an artist and no one knew about this treasure trove of artwork. So we’re seeing a lot of interest and a lot of excitement,” Reuters quoted Helen Hall, director of popular culture at Bonhams, as saying.

The works for sale come from the collection of Rodney Hilton Brown, who worked with Ali on his art.

Ali, the former world heavyweight champion, announced his conversion to Islam in 1964 when he hit the peak of his international career. He died in 2016 at age 74 after a battle with Parkinson’s disease.

"The Starving Children of Mississippi," from 1967, shows a figure in shorts saying “I only wanted to fight to help feed you poor Black kids."

"There’s one that references the race riots in L.A. and Newark in ’65 and ’67," said Hall.

"One of the paintings is devoted to Islam. He had just recently converted. And then some of them have a lighter tone and relate to boxing."

Other works include “America: The Big Jail” from 1967, and “War in America” which has a pre-sale estimate of $25,000 to $35,000.