Answer: The English Bible
Step-by-step explanation:
The Pilgrim's Progress from This World, to That Which Is to Come is John Bunyan's famous work of theological fiction, which dates back to 1678. The primary source for this allegory is the English Bible. Since The Pilgrim's Progress is a Christian allegory, it includes many of the Bible's themes, such as the perseverance in the Christian faith. In this book, a man called Christian travels from the "City of Destruction," to the "Celestial City", which is interpreted as Heaven. During this journey, he carries a book which is possibly the Bible itself.