;)
In the middle ages in Europe back when basically everything was about religion, paintings tended to be didactic, or morally instructive. The objective was to teach the illiterate how to behave and to basically teach society right from wrong.
So the lesson was pretty simple..., stay away from immorality in the form of wine, woman and song and live a puritanical, devout and pious lifestyle, in other words avoid sin, thereby positioning yourself for a much better fate in the afterlife.