In Introduction to Talmud Eser HaSefirot, Baal-HaSulam brings down the key steps in the spiritual ladder that one follows to attain HaShem. His explanation is very complex and I hope that this diagram along with brief summary can help you understand this approach. Click on Diagram to see it in full mode.
Step A – called Hester Kaful, i.e. Double Concealment of face of HaShem. This step is alluded to in the book of Devarim when Moses tells people that if they continue doing evel deeds HaShem will hide His face (Step B), and a sentence later he follows up by saying … and if you proceed with idolatry I’ll “Hester Astir” – I’ll hide [twice the same word is repeated] My face from you. Baal HaSulam explains that in this phase a person doesn’t believe that HaShem rules the world and therefore the person attributes everything that happens to him to forces of nature of unfortunate or fortunate sequence of events around him. This phase is called “Rasha Gamur” – Complete Wicked person and every sin that person performs by being in this stage in considered to be intentional.
Step B – called Hester Echad, i.e. Single Concealment. It’s also called in Kabbalah “Hester Panim ve-Achoraim Megulot”, i.e. The Face [of HaShem] is hidden, while His back is visible”. Baal HaSulam brings a mashal (example) about a person who went to meet his friend. The person sees his friend from behind and therefore while he suspects that it is indeed his friend, he isn’t completly sure. This explains the state that the majority of people are at right now – we logically acknowledge that HaShem exists and rules the universe, however we still have hard time to accept that everything that happens to us and around us is done by Him. We see good people having hardships in their lives while wicked are getting richer, we see people dying in masses (Holocost for example) while crooks get away with their evil deeds and while we suspect that HaShem exists we can’t attribute these events to His ruling of the world. This phase is called “Rasha Eino Gamur” – Incomplete Wicked person and every sin that this person performs during this stage is considered non-intentional.
Step C – called Gilui Alef, i.e. First Revelation of HaShem’s face. When person reaches this stage he is no longer logically comprehends that HaShem rules the world, but he CLEARLY SEES IT. Therefore at this stage, the person ascends beyond material concepts of space and time and clearly sees that everything that HaShem does is done via the system of Reward & Punishment. Baal HaSulam explains that a person can’t reach this level by himself as it is beyond his abilities – only when a person invested all his strength in Torah & Mitzvos and has done absolutely everything that was humanly possible to serve HaShem, then HaShem lifts him up and brings him to this level. Baal HaSulam also brings down a pasuk that says that HaShem becomes guarantee for this person and guarantees that this person never will fall from this level. Baal-HaSulam explains this point by the fact that once person ascended beyond limitations of our physical world, he can clearly see what tremendous benefit each mitsva brings to him and what spiritual damage each sin brings to his soul, thus as any normal person wouldn’t cut his own hand and will always rush to get a million dollar, Tzadik will never pass on a mitsva and will run away of any possibility of the sin as we would have ran from fire. Thus Tzadik comes from the word “Matzdik”, i.e. justice, as he always justifes the ways of HaShem as he can clearly see that they’re being done via the system of Reward & Punishment. At this phase all his privious Intentional Sins convert to be Unintentional Sins on the merit of this stage. The person called “Tzadik Eino Gamur” Non-complete Tzadik when he reaches this stage.
Step D – called Gilui B, i.e. Full Revelation of HaShem’s face. When person reaches this stage in addition to seeing that HaShem rules the world via the system of reward and punishment, he can also see that each action of HaShem comes as pure love toward each one of us – regardless of how good or evil a human being is. At this stage the person sees the picture of our universe completely – all the spiritual roots & worlds in addition to full comprehension that HaShem only does good to His creations. A person on this stage is called “Tzadik Gamur” – complete Tzadik and his previos sins are being converted to MERTIS as person was able to overcome them and get to this highest stage of spiritual development.