The overarching message of the still life is that the physical world is seductive, yet you are not to be seduced. God’s creation teems with beauty and pleasures, yet these will pass away, and you should not be so consumed by the physical world that you starve the soul. You are called as a Christian to look beneath or beyond the surface. That is why so often the interior of still-life elements are quite literally exposed to sight: We see into the lemon, the bread, the oysters; we see through the clear glass and wine, and shining surfaces reflect an unseen world.
All this was well-understood in the 17th century. Some early still lifes were more labored in advertising their moral intentions than others; the artists added crucifixes and other religious items in the shadows around the alluring foreground objects, or painted slips of paper encumbered with phrases like " Vanitas vanitatum et omnia vanitas " or "Jesus, the most beautiful flower of all."
Later on, the genre did in fact descend from the higher principles it began with into the showy decorativeness and technical display its critics had said it had always evinced. The moral lessons were subordinated to trompe l’oeil illusions and amusing coded pictures of the five senses, the seasons, and the like.
But the still life survived into the Modern era, outliving much of the "serious" art of its day, which today can strike us as too limited in its appeal or subjects, too tied to issues long past relevance. Because their symbolic language is so flexible and derived from familiar sources, still lifes remain as captivating, beautiful, and enigmatic as they were for the 17th-century Dutch. The timelessness of the still life should remind us of the passage of time and the approach of eternity. (Michael Schrauzer, This Rock