Hello. It is only possible to explain this quote satisfactorily, if the full text is read. Unfortunately you have not informed us which text this quote belongs to. In the meantime, I will try and help in the best possible way.
In general, we can say that the quote shows that the narrator needed to change something in his life, but that he could not see that need, or how to start that change, or even, did not know how to change. However, Jonas, did something that made everything very clear and signaled to the narrator how and why the change should be made. To understand how this happened, you need to read the entire text and find a better context for both the change and Jonas' participation in it.
