St. Joseph accompanies Mary in her prayer. An image of protection, he is holding his cloak out and over the scene, catching the incense. He is playing a role akin to the domes above Eastern churches: catching the incense of prayer and sending it to Heaven. St. Joseph is the Patron of the Church, the Body of Christ, and as such he catches and collects our prayers, striving that none should be lost to the dark night. As the shadow of God the Father, he provides a bulwark against the cold, and watches humbly from the background, making sure that his cloak reflects light onto the Christ Child and His Mother. See: http://elanartgallery.blogspot.com/ .