"Only when there are challenges can there be motivation, and only when there is motivation can there be progress", that is to say, only when faced with challenges and difficulties can we stimulate our inner motivation and drive ourselves to make continuous progress and growth.
The phrase "only when there is challenge can we have motivation, and only when there is motivation can we make progress" tells us that in the process of pursuing growth and progress, we will inevitably face challenges and difficulties, but it is the tempering of these challenges that makes us stronger and achieve higher-level achievements.