Question: In which book is crossing the Machsom (Barrier) described? Could it be that I have crossed it already and haven’t noticed?
Answer: You can learn about this by reading the material by Baal HaSulam on the subject of Tzimtzum Aleph.
Answer: First they are his friends on the path of spiritual development and then all those who are attached to it.
Question: What is “good” in spirituality, and in what way is it different from the materialistic “good?”
Answer: Good in spirituality represents the absolute good that leads a person to the purpose of his creation.