What separates the simply talented from the brilliant in each and every art, science, and skill-set is endless repetition of physical and mental exercises. Only then does one go from being competent to being as nearly perfect and well-honed as he can be. What R’ Salanter realized was that that also goes for the ability to grow in one’s being. In order to excel spiritually we have to polish and repeat our efforts again and again, too.
So he advised us to engage in this exercise: we’re to repeat to ourselves over and over again certain aphorisms that touch us and lay out a truth clearly and succinctly until they become engraved in the tablet of one’s heart. That is, until they become our mottos for life. Do that whenever you have a spare moment night and day, and “the statement will ring in your ears like a bell and never depart from your memory” he assured us.
Imagine constantly and earnestly repeating this verse that refers to putting your trust in G-d’s decisions in your life: “Place your hope in the L-rd. Be strong and let your heart take courage. Yeah, place your hope in the L-rd” (Psalms 27:14). With that and other such maxims on your lips all the time you can’t help but sense G-d’s effusive presence in your life.
Or imagine what repeating the verse, “G-d created Man in His image, in the image of G-d He created him” (Genesis 1:27) would affirm in your being about your G-d-given abilities and purpose. Say other such verses (as well as certain like Talmudic statements) often enough and in a heart-felt way, and you can’t help but assimilate their wisdom and to grow.
In fact, we’re assured that R’ Salanter himself engaged in this practice his entire life long. As R’ Blazer reports in his recollections of his teacher, “R’ Salanter would (ordinarily) study Mussar texts with great fervor, in a delightful voice that stirred feelings of solemnity” in those who overheard him. In the middle of that, though, he’d oftentimes “stop his studies to focus on a certain statement and to repeat it again and again” along the lines of what we’d cited above. And he’d sometimes “burst into tears” in the process, touched by the rank truth of what he heard himself saying.