Siman 570

(127.) I heard from the mouth of Rabbainu o.b.m. — that he said regarding young people who were complaining to him about the troubles of their souls: that they do not merit to become holy in truth and serve G-d as is fitting. And once he answered and said there are counsels that would certainly help. "But even the counsels themselves are difficult to fulfill." (Likutay Halachos, Laws of Eruvin, Law 5, letter 25.)