The subject of the painting appears to be from the Gospel of Saint Luke, 5: 1-11, which tells of one of Christ's miracles, and his calling of Simon Peter, James and John to follow Him. Standing by the Sea of Galilee, Christ sees two boats at the shore and their fishermen washing their nets. He enters Simon's boat, and after preaching to a crowd of followers on the shore, tells Simon to go out upon the lake and cast his net. Simon protests that they have taken nothing all the previous night, but at Christ's bidding will try again. Their net fills with so many fish it breaks; they call to the other boat for help, and both boats become so laden with fish they begin to sink. Simon, James and John are amazed and fearful, for they feel unworthy of such a miracle. Christ tells them not to fear, "for henceforth thou shalt catch men. . . . they forsook all, and followed him." Tanner was not a literal illustrator of Biblical stories. He distilled their spiritual essence by reducing all representative details to a few essentials and rendering these in a nearly expression is the style.