In chapter 8, why is Gatsby's love for Daisy described religiously? What is Fitzgerald achieving by this?
In chapter 8, Gatsby describes the time when he (along with other soldiers from his army camp) first met Daisy. He fell in love with her and felt a "breathless intensity" about her house, as it was suffused with mystery. He describes her in terms that make her seem like an untouchable goddess. For example, before he must leave her, he touches the ends of her fingers gently. To him, her house is like a temple, pervaded by mystery and the wonders of great wealth.
The reason that Fitzgerald brings these religious-like memories that Gatsby has of Daisy into chapter 8 is that they remind the reader why Gatsby is willing to sacrifice himself for her. She is not just human to Gatsby; instead, she is sacred to him. Nick tells Gatsby to leave his house to avoid the trouble surrounding Myrtle's death, but Gatsby won't leave until he knows that Daisy is safe; ultimately, this means sacrificing himself for Daisy.
Nick says that Gatsby fell in love with Daisy almost by accident. He had only intended to "[make] the most of his time" with her, and he "took what he could get": he slept with Daisy, having given her a false impression of his fortune and pedigree. Once he did fall for her, however, Nick says, "he found that he had committed himself to the following of a grail." The grail to which Nick refers is the cup believed to have been used by Jesus for wine at his last supper. A great many explorers and archaeologists have sought and devoted their lives to the seeking of the holy grail, and none have been successful. Nick's description seems to convey the idea that the quest for Daisy, for her love and for her hand in marriage, will be similarly unsuccessful for Gatsby. It has all the mystery, mysticism, and beauty of the original grail quest, at least for Gatsby, but the statement foreshadows its impossibility and ultimate failure.
In Chapter 8, Jay Gatsby discovers that "he had committed himself to the following of a grail." The religiosity of this turn of a phrase is multi-layered. First, Daisy is goddess-like to Jay. Putting someone so far above oneself immediately places them in the realm of the unattainable. In addition, making Daisy a pseudo-goddess means that Gatsby, a mere mortal, is unworthy of her love. Finally, and most importantly, the quest for the "grail" is the same thing as chasing the impossible. Historically, those who have thought that the grail was within their grasp have suffered the ultimate disappointment of watching it slip from their hands.