So despite the fact that the SAB has no notes on chapter 4, there's a lot here that I really think is noteworthy, including the fact that there are no notes despite the presence of certain items.
Israel goes to battle against the Philistines, and early in the fighting, they sustain casualties in the neighborhood of 4,000. The SAB doesn't mark this attack against Israel as violent, unjust and intolerant, despite the fact that I'm certain it would had the roles been reversed. What's up with this? I only ask for consistency here.
Now, as things are going pretty badly, some people get a bright idea: Since it served them so well in the days of Joshua, why not run back to Shiloh and fetch the ark of the covenant, and take it into battle? So they send for it, and Eli's sons bring it to the front lines. At first, it seems this might do them well, as the Philistines get worried. In the end, things go worse for them as the Israelites discover that the ark isn't some sort of battle-winning magic charm. This time 30,000 of them are struck down (still no comment from the SAB, although I think Steve Wells might reasonably add these folks to his list of people killed by God, as I think they lost this battle to be taught a lesson), including Eli's two sons, thus fulfilling the prophecy.
A man runs from the battle back to Shiloh to inform Eli of what has happened. Eli, being old, blind, and overweight, falls over backward at the shock of the news, and breaks his neck. When his daughter-in-law hears the news, she goes into labor and gives birth to a child, who is named Ichabod ("no glory") to commemorate this terrible day in Israel's history. (It sounds as though she may have died in giving birth, too, but it's not fully clear.) Pretty much all of the misfortune that befalls Israel in general and Eli's family in particular is the result of dealing with God in a far too casual manner.
Of course, the Philistines aren't going to have a good time of this, either.