“Christ, I did not know he was so big.”
“I’ll kill him though,” [Santiago] said. “In all his greatness and his glory.”
Santiago’s expletive (“Christ”) and the laudatory phrase “his greatness and his glory” link the fish’s fate to Christ’s. Because Santiago declares the marlin his “true brother,” he implies that they share a common fate. When, later in the book, sharks attack the marlin’s carcass, thereby attacking Santiago as well, the sense of alliance between the old man and the fish becomes even more explicit.