Campin's Merode Altarpiece is not only an example of a fine oil painting but is also a definitive painting of the Northern European Renaissance. It is a triptych, which is a painting on three hinged panels that can be folded together. The three panels of Campin's altarpiece show three images: the donors of the work kneeling in a garden, the Annunciation, and Joseph working in his carpentry shop.
First off on the left panel we see the patrons who commissioned Campin to paint this. They are kneeling humbly and the woman is holding prayer beads, so it's safe to say these patrons wanted to be remembered for their religious devotion. The man has even removed his hat.
On the right panel is Joseph the carpenter seen with woodworking tools of the time. Campin took time to paint the realistic wood shavings, nails, and lines—stunning attention to detail. The tools at the bottom of the picture serve as hidden symbolism, something Campin mastered. The saw, axe, and rod all refer to Isaiah 10:15.
The center panel, the Annunciation, contains lots of symbolism, so take another look.