In both The Tempest and Robinson Crusoe, books serve as a crucial part in the survival and livelihood of the main characters who have been estranged from their way of life. For Prospero, his books gave him his magic, which not only gave him the power to control others on the island but also the power to perform his revenge. For Robinson Crusoe, the Bible gives him solace and the strength to continue with his solitary life on the island. He turns to God for strength while sick through reading passages from the Bible, and after that believes that God was saving him from his old ways by marooning him on the island. Therefore, the Bible plays the same role for Robinson Crusoe as the magic books play for Prospero, even though the manner in which these books serve the characters is extremely different.
The Bible that Robinson Crusoe reads also brings many of the religious references in his story to the forefront. After his first voyage at sea, Crusoe contemplates returning home as the prodigal son does in Luke 15:11-32, and compares his return to that in this parable. The biblical story of Jonah and the Whale is also alluded to, as Crusoe neglected his duty to his father and was punished at sea, as was Jonah. Once on the island, Crusoe believes he has been put there to see the errors of his ways and repent, comparing his rebellion against his father to the original sin of Adam and Eve (Defoe 142), and therefore comparing his exile from the rest of the world to the expulsion of Adam and Eve from Eden. In large sections of the book the major theme is repentance of sin and turning to God. He constantly thanked God for his provisions and deliverance from sin, and when on the brink of death (Defoe 63-64) the angel came to him in a dream and told him he needed to repent he relied on God and the Bible even more.
Even though Robinson Crusoe and Prospero both find their sources of strength in books, the fact that Crusoe takes his strength from God and Prospero takes his strength from magic and revenge makes these two works very different, because they teach very different lessons. Defoe uses Crusoe and his Bible to teach repentance and faith, while Shakespeare uses Prospero and his magic books to teach a lesson on forgiveness.