I am beginning a review of a book asking whether the story of David and Jonathan, who 'loved' each other, is relevant to gay Jews and Christians. These comments are by way of preparation, before reading the book.
First, the story is a story and not factual, so we need to consider why the biblical author found this to be a theme worthy of exploring. Jonathan was son of King Saul, who dynastically might expect to be the next king. However, Saul is depicted as the first king, before the dynastic principle was established. The Samuel narrative is antagonistic to Saul, who has black moods, attempts to kill David, and finally consults a spirit ('witch') in Endor. The reader knows that David will be the next king, because Samuel anointed him, but we cannot be sure that Saul does. Before Samuel, the Judges narrative vilifies Saul's tribe, Benjamin, through the story starting with the rape and murder of a Levites' concubine. But for the grace of the other tribes, Benjamin would have been wiped out. Viewed as political propaganda in the writer's own period in the 4th century BCE, this story cuts the tribe of Benjamin down to size. Saul had many faults and many stupid policies: but his fundamental crime was to have offered sacrifice himself in Samuel's absence. At its heart, then, this story is about priestly monopoly.
Into this background, David the future king, and Saul's son Jonathan have a positive and friendly relationship which utterly contrasts with the fear and suspicion that Saul had. The whole story is one of bloodthirsty battle between Israelites and Philistines, and civil war between Saul and David. David is presented as an innocent party, not killing Saul opportunistically in order to take the throne. Even when given the throne by an Amalekite, Saul's killer who wished to ingratiate himself, he avenged Saul's death by killing him. So his hands were seen to be clean. David had married Saul's daughter (the bride price had been 100 Philistine foreskins, set to ensure David was killed) and treats Jonathan as the closest of brothers. Saul himself was the problem, not his family or his troops. "An evil spirit from the LORD tormented him" (I Sam 16.14)The friendship was instant - "the soul of Janathan was knit to the soul of David, and Jonathan loved him as his own soul" (1 Sam 18.1). Jonathan made a covenant with David, and gave presents of clothes and weapons. He "delighted much in David" (19.1) and warned him that Saul had put out orders to kill him. They make another treaty of loyalty before David escaped "Jonathan made David swear again by his love for him; for he loved him as he loved his own soul" (20.17).
The treaty bound together David with Saul's house in perpetuity, thus protecting Benjaminites in the author's own day. The savage critique of monarchy under Saul should not adversely affect tribal relations at the time when the story was told.