Baal HaSulam, Letter 13: This happened to you due to negligence in my request to exert in love of friends, as I have explained to you in every possible way that this cure is enough to recompense for all your faults. And if you cannot rise to heaven, then I have given you moves on earth. So why haven’t you added anything in that work?
A person cannot be constantly directed at the Creator and constantly strive to Him as the foundation of all one’s feelings and thoughts. However, friends can elevate you to this level and then you will not have to make great efforts and have excessive inner tension in order not to break away from the Creator, because the group will be supporting you.
However, first we must try to go through this by ourselves for some time. A person will then realize that with the help of the group, one can easily, even without effort, solve this issue: the group will work for you and you for the group. This is much easier.
Baal HaSulam, Letter 13: Besides the great cure that lies within it, which I cannot interpret, you should now that there are many sparks of holiness in each one in the group. When you assemble all the sparks of holiness into one place, as brothers, with love and friendship, you will certainly have a very high level of holiness for a while, from the light of life, and I have already elaborated on that in all my letters to the friends.
Sanctity is bestowal, love, and reciprocity, which is manifested between the friends because it is a spiritual quality.
From the Kabbalah Lesson in Russian 2/11/19