Jim Bob Duggar admitted that his emotions have been strong. "I've been crying half the day, so I'm making jokes to keep from crying," he told guests at the rehearsal dinner.
Derick's mom, Cathy, is battling cancer and was unable to attend the rehearsal.
"I want to ask everyone to pray for my mom," Dillard told PEOPLE. "Anyone who has been through [cancer] knows what it is like, and if everyone could think of her, I know she would really appreciate it."
Derick is hoping that his mom and step-dad, Ronnie, will be able to attend the wedding today.
For dinner, guests enjoyed brisket, chicken legs, baked beans, hash brown casserole, deviled eggs, and ice cream sundaes. Jill and Derick listened to family and friends share memories and marriage advice.
The Duggar kids also put together a hilarious movie reenactment of the couple's engagement.
Read more at PEOPLE.com.