Among the outstanding German artists of the period around 1500 was Hans Baldung Grien, a printmaker and painter. He produced book illustrations, devotional woodcuts, stained-glass window designs, portraits, and morality paintings as well as religious panels such as this one.
John the Baptist is here depicted to the left of Jesus. He simultaneously gestures to the lamb at his feet and to the infant, visually alluding to his own description of Christ as "the Lamb of God." The Virgin's mother, Saint Anne, although dressed in a sixteenth-century wimple, wears her traditional robe of red, a symbol of divine love. Garbed in green, symbolic of rebirth and eternal life, Mary offers Jesus an apple. This fruit, associated with the fall of Adam and Eve, here signifies Mary as the new Eve and Christ as the second Adam.
Baldung Grien's figures are symbolically, rather than realistically, depicted. Mary, for instance, is represented as a very young girl. And, although John and Jesus historically were about the same age, the Baptist is portrayed as an adult to emphasize his prophetic message. The painting was discovered in a small village church in Alsace, an area where the artist spent most of his life.
More information on this painting can be found in the Gallery publication German Paintings of the Fifteenth through Seventeenth Centuries, which is available as a free PDF https://www.nga.gov/content/dam/ngaweb/research/publications/pdfs/german-painting-fifteenth-through-seventeenth-centuries.pdf