What theme is represented in andrea pisano's doors of the baptistery of san giovanni in florence?

The Baptistery has three sets of bronze doors with relief sculptures. Andrea Pisano has created the south set of doors, which have two valves and each valve has 14 square panels. The twenty panels on the upper part show scenes from the life of John the Baptist. The eight panels on the lower part represent the eight virtues of faith, hope, humility, fortitude, charity, temperance, justice and prudence.