Who said "Even with his head cut off, a fighter can do one more deed."?

Yamamoto Tsunetomo (1659–1719). Source: Hagakure, Book 1.

What is the original Japanese?

首打落させてより、一働きはしかとするものなり. Translated from the original Japanese by Spartan Surfers.

Even with his head cut off, a fighter can do one more deed.

The source

"Even with his head cut off, a fighter can do one more deed." Yamamoto Tsunetomo said it in Hagakure, Book 1. Translated from the original Japanese by Spartan Surfers.

"首打落させてより、一働きはしかとするものなり"

Original Japanese, Hagakure, Book 1. Japanese: Hagakure, vol. 1 (1937 printing), NDL digital text.

Who said it

Yamamoto Tsunetomo (1659–1719). Samurai turned monk whose spoken reflections were written down as Hagakure, Hidden by Leaves.

Questions

Who said "Even with his head cut off, a fighter can do one more deed."?: Yamamoto Tsunetomo (1659–1719). Source: Hagakure, Book 1.
What is the original Japanese?: 首打落させてより、一働きはしかとするものなり. Translated from the original Japanese by Spartan Surfers.