Ellie and Brenda won't wear new clothes to church because their father got laid off.

The Aarons family stopped regularly attending church after their mother got into a fight with the preacher. For the past three years, they've only gone at Easter. Their mother always buys them new clothes with whatever money they can afford so that they look good during that one visit.

However, this year, Mr. Aarons came home from Washington because he was laid off just before Mrs. Aarons was going to take the girls to Millsburg Plaza to look for clothes. This means that there wasn't enough money for new clothes for the girls to wear like normal. They don't want to go because they think they'll be embarrassed by the clothes they have to wear.

They do end up getting at least one new item each, though, as part of a compromise to go to Easter service.

In Chapter 8: Easter (in Katherine Paterson's novel Bridge to Terabithia), Jess's sisters, Brenda and Ellie, are really excited because they always get to wear fancy new outfits to church on Easter.

This may not sound like a big deal to most readers or a reason to get particularly happy, but because their family has very little money, these girls hardly ever get to wear new things. But their mom thinks it's important for them to look nice on that holiday, which is why she's always let Ellie and Brenda have new Easter outfits in the past.

If you take a look at the second paragraph of Chapter 8, you'll see why the girls are disappointed, though. Instead of getting to go shopping with their mom for new outfits, they learn that their dad has just lost his job. With no money to spare, there won't be any new clothes. The narrator of the story drops the news on us in two short, staccato sentences: "He'd been laid off. No new clothes this year."