Source: In Xunzi's "Cultivation", "Although the Tao is dense, it cannot be done; Although things are small, you can't do it without doing it "is the source of" although the road is far, the line will come, although things are difficult, you will succeed if you do it ".
A similar quote:
Persisting in the great cause of will requires perseverance. -Voltaire
The most terrible enemy is that there is no firm belief. -romain rolland
Will lies in tempering, and success lies in persistence. Zhou Haizhong
As long as you have strong willpower, you will naturally have ability, intelligence and knowledge. -Dostoevsky