Training without huge self-belief goes nowhere.

The source

"Training without huge self-belief goes nowhere." Yamamoto Tsunetomo said it in Hagakure, Book 1. Translated from the original Japanese by Spartan Surfers.

"凡そ修行は、大高慢にてなければ役に立たず候"

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 "Training without huge self-belief goes nowhere."?

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

What is the original Japanese?

凡そ修行は、大高慢にてなければ役に立たず候. Translated from the original Japanese by Spartan Surfers.