Masaccio, The Pisa Polyptych: St. Julian Slaying His Parents, St. Nicholas Saving Three Sisters from Prostitution

Tempera on panel
Staatliche Museen zu Berlin, Gemaldegalerie, Berlin, Germany

From the predella. This panel is notable for its bold emotional program, where visual similarities underline moral opposites. The two saints lift their right hands in nearly identical gestures, one to kill and the other to give. The woman in the alley raises her right hand also, in a gesture of invitation to the prospective john, whose curly hair repeats that of the two saints.  The narrowness of the two alleys is another visual similarity that speaks to moral difference.

More of St. Julian
More of St. Nicholas

Source: Olga's Gallery