In Letter #38 from the book Fruits of Wisdom, Baal HaSulam writes to his foremost student and son, Baruch Ashlag (Rabash) that a person cannot give up and stop in the middle of the spiritual path. Until a person reaches the goal, he needs the force of constantly overcoming greater and greater obstacles.
You cannot rely on past victories. On the contrary, everything you attained yesterday turns into a new desire today, which pushes you toward the goal even more. Therefore, the things you received yesterday cannot heal your wounds and let you rest.
Until a person attains the final correction, he must take care to ensure that his desire to reach the goal grows at every moment. Everything you attained immediately disappears. A person remains "naked" and that’s how he has to advance.
Obviously, Rabash performed a huge task while being next to his father, constantly being by his side and participating in all the lessons. He was very loyal to his father and always took his side in all the family quarrels that emerged among Baal HaSulam’s relatives. Some of them were opposed to the study of Kabbalah because it set them apart from the religious community.
Rabash was a successful student and he attained spiritual revelation. We cannot tell what height he rose to; he is too great for us to be able to measure that. We can only surmise about his greatness and his huge heart based on the explanations he gave to our states and the need to unite.
We don’t yet realize how deep his articles are and how vital his practical advice is. That is why we must study them all the time.
While working on the articles, the most important things are: 1) to make a concise summary of each article, and 2) to draw conclusions from the summary. Without doing this work, we are not really studying the articles.
From the 4th part of the Daily Kabbalah Lesson 9/12/10, Baal HaSulam, Letter 38