A similar view of work was presented in 1981 by Pope John Paul II in his Encyclical Letter, Laborem Exercens. Integrating some themes found in Marx with more traditional Catholic theology, the Pope claims that "work is one of the characteristics that distinguish humans from the rest of creatures.... Only humans are capable of work, and only humans work." Citing the Genesis story in which humans are created "in the image and likeness of God" and in which humans are called forth "to subdue the earth," the Pope argues that work is an essential part of human nature. These Biblical passages suggest that humans are meant to be co-creators (made in the image of God the creator) in shaping the earth and using it to maintain their life on earth.