Who said "Stuck? Shake it off and start fresh."?

Miyamoto Musashi (c. 1584–1645). Source: The Book of Five Rings, Fire (Renewal).

What is the original Japanese?

我氣を振捨て、物毎をあたらしくはじむる心に思ひて. Translated from the original Japanese by Spartan Surfers.

Stuck? Shake it off and start fresh.

Miyamoto Musashi, The Book of Five Rings, Fire (Renewal)

The source

"Stuck? Shake it off and start fresh." Miyamoto Musashi said it in The Book of Five Rings, Fire (Renewal). Translated from the original Japanese by Spartan Surfers.

"我氣を振捨て、物毎をあたらしくはじむる心に思ひて"

Original Japanese, The Book of Five Rings, Fire (Renewal). Japanese: Miyamoto Musashi (Kinkodo, 1909), NDL digital text.

Who said it

Miyamoto Musashi (c. 1584–1645). Undefeated swordsman who wrote The Book of Five Rings in a cave a few weeks before he died.

Questions

Who said "Stuck? Shake it off and start fresh."?: Miyamoto Musashi (c. 1584–1645). Source: The Book of Five Rings, Fire (Renewal).
What is the original Japanese?: 我氣を振捨て、物毎をあたらしくはじむる心に思ひて. Translated from the original Japanese by Spartan Surfers.