Final answer:
Saul faces the challenge of being blinded by light and hearing a voice while on the moose in the painting 'The Conversion of Saint Paul' by Caravaggio.
Step-by-step explanation:
Saul faces several challenges on the moose in the painting 'The Conversion of Saint Paul' by Caravaggio. First, Saul is blinded by a bright light while hearing a voice, which symbolizes his conversion to Christianity. This challenge changes his entire perspective and belief system. Second, the other soldiers in the painting appear frightened by the light, reflecting the turmoil and conflict Saul's transformation creates within the group. Lastly, Saul's horse is depicted as uncontrolled and recessed into the background, symbolizing the loss of control and uncertainty Saul experiences during this transformative moment.