Guy: You lost today, kid. That doesn't mean that you have to like it.
[Nazis burst into the room where Indiana and Henry are, and they put their hands up.]
Nazi: Dr. Jones?
Indiana and Henry: [at the same time] Yes?
Henry: Come on, Junior.
Indiana: Will you please stop calling me Junior?
Sallah: Please, what does this mean? Always with this Junior?
Henry: That's his name: Henry Jones, Junior.
Indiana: I like Indiana.
Henry: We named the dog Indiana.
Sallah: The dog? You are named after the dog.
Marcus: Can we go home please?
Indiana: I have a lot of fond memories of that dog.
[Henry has activated a secret lever which rotates him and Indiana from a room on fire to a room full of German soldiers.]
Henry Jones: Our situation has not improved.
[Over the deafening noise of ship engines.]
Indiana Jones: Are you crazy? Don't go between them!
Dr. Elsa Schneider: Go between them? Are you crazy?
Elsa: What's this?
Indiana Jones: Ark of the Covenant.
Elsa: Are you sure?
Indiana Jones: Pretty sure.
Henry Jones: I didn't know you could fly a plane!
Indiana Jones: Fly, yes! Land? No!
Henry Jones: Those people are trying to kill us.
Indiana Jones: I know Dad!
Henry Jones: It's a new experience for me.
Indiana Jones: It happens to me all the time!
[After tossing Col. Vogel out of a zeppelin window, Indy looks back at the stunned passengers.]
Indiana Jones: No ticket.
[Everyone madly scrabbles for their tickets.].
[After flying through the burning wreckage of the plane that passed them in the tunnel.]
Henry: Well, they don't come any closer than that.
Indiana Jones: He's got a two day head start on you, which is more than he needs. Brody's got friends in every town and village from here to the Sudan. He speaks a dozen languages. Knows every local custom. He'll blend in, disappear, you'll never see him again. With any luck, he's got the grail already.
Henry: I suddenly remembered my Charlemagne. Might my armies be the rocks and the trees and the birds in the sky.
Answer: Henry says, in response to Indy asking if he remembered the details of the trials: "I wrote them down in my diary so that I wouldn't have to remember." So, obviously he did NOT know them by heart. Also, as the other answer says, they didn't want the diary to either be in the Nazis' possession or be burned.