Behold, there is a ladder standing to be able to mount the mountain of Hashem and to acquire purity of the soul. It is the constant study and hearing of words of Mussar, for through this he will learn to fear Hashem. When a person reads these works of Mussar, he will find that he is full of sins and iniquities, for he will find that things which he has done and thought that there was nothing wrong with them, that they will actually be a great sin. Examples of this are theft, causing pain to a friend, false and wasted vows, making fun, flattery, falsehoods, snatched blessings, wasted words, bad speech (which in its degree of severity is compared to idol-worship), forbidden relationships, blood spilling, arrogance, anger etc. and above all wasting time from learning Torah.
All of the above are very bad sins, which the general public have accustomed themselves to violate, to the extent that they are considered to be permitted. If, however, one accustoms oneself to read or listen to works of Mussar on a daily basis, “the learning will descend like rain!”, so that just like rain can pierce a stone, so too words of Mussar end up piercing even a heart of stone. He will move step by step along the good path, and his heart will understand and heal itself bit by bit.
