The most significant of the four scenes of the altarpiece is the Flight into Egypt. The Gospel according to St Matthew relates this episode in a few succinct words: "And Joseph rose and took the child and his mother by night, and departed to Egypt." With only this brief indication from the original text, painters have always had to draw on other sources in order to add flesh to their images.
In the Dijon altarpiece, the Virgin is seen in profile, riding side-saddle on a small donkey. She holds the baby Jesus pressed to her cheek. He is wrapped in swaddling bands, and she has drawn her large cloak up around him. The child and his mother are looking at each other. St Joseph is leading the donkey by the halter, while he pours drink into his mouth from a small keg. He carries a stick over his left shoulder, from which his coat and a small pot with a ladle have been hung. He is wearing a hood and a surcoat held in by a leather belt at the waist. He has slipped his purse under the belt, and his leather boots seem to have been worn out by the long journey he has made on foot. He has a hooked nose, a curly beard and bushy eyebrows. The forbidding empty landscape, the meditative introversion of the figures, and Joseph's peasant humour express a piety appropriate to the Carthusian monastery for which the scenes were destined.
The Holy Family have turned out of a sunken road running alongside a stream, and are about to climb a twisting path that leads away to the right across an arid mountainside. In the foreground, the water that wells up out of the rock is collected in a small rectangular basin, from which it pours out through a spout to flow away freely once again. At the foot of the mountain stands a small statue of a warrior, armed with a lance. The statue has been broken in two, an allusion to the end of idolatry. A castle is perched high up on the peak of the mountain, well above the scene.
The heads of the Virgin and Child, unlike that of Joseph, are both surrounded by a golden halo. Indeed, Joseph hardly corresponds to the conventional idea of a saint at all. Broederlam has portrayed him as a rough working man, a tired labourer weighed down by his heavy clothes. Some have even called him a tramp, and suggested that it may not be water with which he is slaking his thirst, but something stronger. Perhaps such stern judgements are themselves merely one reflection of the ambivalent cult that grew up around the figure of Joseph towards the end of the Middle Ages, for it was at that time that he began to be openly caricatured, and depicted as a peasant who deserved to be ridiculed rather than revered. What really distinguished Broederlam's Joseph, however, is the fact that he is the only ordinary man in the whole altarpiece. He marks the first appearance in painting of an irremediably earthbound reality. From then on, from the Van Eyck brothers to Quentin Massys, this reality would be a constant theme of Flemish artists, even though their work was essentially religious in inspiration. Henceforth, there would be a continuous and growing emphasis on the physicality of the figures depicted, and the details of their appearance, as artists sought to capture their individuality by endowing them with a tangible presence. It is in this sense that Broederlam's Joseph signals the beginning of one of the most significant revolutions in the history of the visual arts.