“The provisions required for this spiritual journey consist of spiritual and ascetic practices to discipline the soul. Since relinquishing material attachments is very difficult, the traveler begins to cut the binding chains of attachment to the realm of multiplicity little by little and leaves the world of physical nature behind.
Hardly before the traveler recovers from the exhaustion of this journey, he enters the intermediate world, which is the world of psychic multiplicity. Here, he clearly realizes how precious are the treasures that material and external multiplicities have stored within his corporeal nature. These are the same imaginal psychic beings that come into being as a result of the traveler’s encounter with and interest in external multiplicities and are considered its outcome and by-products.
These thoughts and preoccupations hinder the travelers wayfaring and take away his serenity and peace of mind. When he wants to take repose in the remembrance of God for a short while, they besiege him like a deluge and threaten his whole being…
It is obvious that the pain and distress caused by psychic multiplicities are more powerful than multiplicities of the physical world. For one can willingly and deliberately retreat and isolate oneself and be saved from disturbance of and encounter with external multiplicities. But one certainly cannot free oneself from the disturbance of temptations and imaginations of the carnal soul, for those enticements always accompany one closely and intimately.
The traveler…is determined to leave behind the realm of temptations that is usually called the intermediate world. However, the traveler must be very alert and careful lest there remain any of those tempting thoughts in the corners of his heart. Because it is a characteristic of these imaginal elements to hide in the most obscured corners of the heart in such a way that the traveler is deceived when he wants to cast them out. He may be fooled to believe that he has freed himself of their evil presence and has been relieved of all remnants of the [the intermediate world]. But when the traveler reaches the spring of life and wants to quench his thirst from the fountains of wisdom, suddenly they attack him and finish him off…
The example of such a traveler is like that of a person who has filled a pool in his house with water but has not touched it for some time. Therefore, all the dirt and impurities of the water has settled down at the bottom of the pool and the water seems clean and clear to him. He assumes that the clarity and purity of the water is permanent. However, as soon as he wants to enter the pool or wishes to wash something in it, suddenly all that dirt and sediment contaminates the clear water again and spots of dirt reappear on the surface. Therefore, through persistent spiritual combat and ascetic practices the traveler must acquire such a degree of certitude and inward peace that imaginal psychic elements are subjugated and cannot disturb his mind when he turns attention to the Beloved Lord.
When the traveler passes through the realm of physical nature, and the intermediate world, he enter the world of spirit…”
‘Allamah Tabataba’i, Kernel of the Kernel, pp. 15-17