What do you mean, you have to tie the bell to solve the problem?

It takes someone who tied the bell to solve the problem, which means: whoever caused the trouble will eventually need to solve it. "Tie" here means hanging a bell with a rope. Synonyms of "he who unties the bell must tie the bell" are "he who unties the bell must tie the bell" and "cardiologist" of heart disease.

The philosophy reflected by "the one who tied the bell must untie the bell" is that "the internal cause is the key factor that determines the development of things". Although external factors can promote or hinder the development of things, it is internal factors that play a decisive role, that is to say, only you can overcome your own shortcomings and get up from where you fell.