As part of the intense research that took several years before production began on The Ten Commandments, Cecil B. DeMille decided to engage an artist skilled in biblical illustration who could ensure historical accuracy and create inspirational images to be translated into film. Arnold Friberg had begun work on the illustrations for The Book Of Mormon when a publisher sent a sample of the illustrations to DeMille at Paramount. At the invitation of DeMille, Friberg journeyed to Hollywood in December 1953 and spent three weeks working with the Director. According to Friberg biographer Ted Schwarz, "[DeMille] would ask him how he might perceive certain characters and Friberg would sketch them in what he felt was clothing appropriate to their day... Both men agreed that Moses should be shown first as a powerful youth, a prince of Egypt and a military leader destined to be the next Pharaoh."
Most of the roles had not yet been cast. Schwarz explains that "[DeMille] occasionally asked Friberg to depict a particular actor or actress as he or she might look in the type and style of dress for that period." The sketches Friberg made resulted in the elimination of a number of major stars, including Audrey Hepburn who had been considered for the role of Nefretiri. The face of Moses in this sketch bears a striking resemblance to actor Henry Wilcoxon, who starred for DeMille as Marc Antony in Cleopatra (1934) and Richard the Lionheart in The Crusades (1935), and had latterly become an invaluable associate producer to DeMille. As Moses had not yet been cast, it is likely that Wilcoxon was asked to model for the role of Moses and that Friberg was asked to sketch him in the dress of the period.
DeMille liked Friberg's concepts, saying to Wilcoxon, "Everything this man does is strong," and offered him the position of costume designer for the film, alongside Edith Head, Ralph Jester, Dorothy Jeakins and John Jensen, with Friberg assigned the leading men. Friberg would also assist in the development of the production by producing sketches and oil paintings which were used to visualise key scenes. After filming completed, Friberg completed a sequence of large oil paintings showing key biblical scenes from the production, which were printed as a souvenir book to be sold at all theatres showing the film, selling over a million copies. DeMille gave credit to Friberg in the souvenir book, stating "His fine paintings were a tremendous help to our art directors, cameramen, costume designers, screenwriters and actors. Arnold Friberg's work has been an inspiration to all of us."
His experience working with DeMille on The Ten Commandments had an enormous influence on Friberg's later work. The statement I believe in God and DeMille was scrolled on the wall of his studio. Friberg explained, "If you had business with God, I believe it would be like dealing with DeMille...I found him to be much greater than the legends they write about him."