Future and simple present?

I've read the following sentence in a book:

"Be careful with the knife, Dad," Peter said, "or you'll cut yourself."

Can I also say:

"Be careful with the knife, Dad," Peter said, "or you cut yourself."

If the two tenses are possible, which one is more common?

In my native language, German, the simple present would be more common.

Thank you in advance.

Veit