The image of Paul in the painting of 1635 is canonical. Why does Rembrandt turn to the image of the Apostle Paul, what did he want to say to his contemporaries, descendants? The answer must be sought in the Epistles of the Holy Apostle Paul - it is this work of his that lies on the table in both paintings, as evidenced by the pen in his hand: the saint is shown writing his Epistles.

Rembrandt's "Apostle Paul in Prison" conveys in detail many of the characteristic features of the work. Rembrandt truly was a master of deep psychology and exploration of the human soul. In this picture, he seems to be trying to convey not only Paul’s physical fatigue, but also his inner world, his spiritual experiences.

The candle lighting, which creates a warm glow in a confined space, and the use of a deep dark background emphasize the intimacy of the moment and focus attention on the apostle's face. Apparently, Rembrandt sought to emphasize the spiritual greatness of Paul, his inner lordship and struggle with darkness.

Your description also perfectly conveys the contradictions in Paul’s appearance: physical weakness, fatigue, and at the same time inner strength, lightness of soul. This is a characteristic feature of many of Rembrandt’s works, who strove for realism in the depiction of human nature and at the same time emphasized spiritual depth.