Literally meaning absorption, diving into, becoming deeply involved in, istighraq (immersion) denotes transportation by joy, oblivion of the world, the cleansing of the heart from worldly worries enabling one to turn to God wholeheartedly, and, in consequence, going into such deep ecstasies that one becomes unaware of even oneself and one is filled with wonder. Those who have acquired love and friendship of God and who have been honored with His special nearness and compliments, travel between love and witnessing the truths that pertain to Him. They throw away whatever exists in their hearts other than Him, fixing their eyes on Him only, becoming absorbed in the observation of His beauties.
Initiates in this state, with the inner perceptions and feelings that come from self-annihilation in God, see everything annihilated in God also. Those who are enraptured with the pleasure arising from such a state cannot help but utter sayings such as “I am the Truth!” or “Glory be to me, how exalted my being is!” Although such sayings issue from mouths under the influence of the spiritual state and pleasure that pervades the being, they have sometimes been taken to be true. It sometimes occurs that initiates cannot distinguish between what is substantial and what is apparent and, confusing their drop-like being with the infinite ocean of Divine Existence, utter unbecoming words of pride that are incompatible with the rules of Shari‘a and irreconcilable with the self-possession that one must have before God. Even if every initiate cannot experience such a depth of self-annihilation and the pleasure that issues from it, most of them feel and experience this state. Some of them are regarded as being directly taught by a great saint who already died or even the Prophet, without needing another teacher or guide; this is called “the way of Uwaysu’l-Qarani.”  Muallim Naji  refers to this way as follows:
See, what kind of immersion you have caused me to experience;
My eyes see you as if you were the tears which they shed.
Immersion has three degrees:
The first degree is the immersion of knowledge in state. That is, in the beginning, an initiate acquires knowledge of some truths, but not being able to experience what is known, he or she is not perfectly conscious of the truth of it. Knowledge is different from experience. Any knowledge concerning the Divine truths is usually theoretical until belief, love and spiritual pleasure become second nature for the initiate. When an initiate feels and experiences these in the very center of the conscience, then knowledge has been absorbed in the spiritual state. This knowledge absorbed and lost in the conscience is the knowledge of a Prophet. We call it knowledge only because at the beginning it is knowledge. At the end of the journey, where this knowledge is completely absorbed and lost in the conscience inciting the initiates to and guiding them in action, it becomes the spiritual state and a station in which the initiates finds peace. With respect to Prophethood, the best description of the initial degree of immersion is in the verse (37:103): When both (Abraham and Ishmael) submitted (to God) wholly, Abraham laid Ishmael down on his face (to sacrifice). The last, perfect degree of this Prophetic knowledge, which has become the Prophetic state, is impossible for us to perceive.
Those whose knowledge has become their state have always been examples to be followed by people. It is difficult to de- scribe such people, even with comparisons and parables. On the other hand, there are others who are described in the Qur’an as, like an ass carrying books (62:5). A scholar unaware of the knowledge he or she has and whose knowledge has not become his or her state is no different from an ass who merely carries the books. Any state which is not based on knowledge is tantamount to heresy and misguidance, while knowledge which has not become a state is ignorance and heedlessness. Straightforwardness through knowledge means rising to a heavenly point on the wings of the state based on knowledge.
The second degree of immersion is the immersion of signs in discovery or unveiling. That is, initiates who have attained the second degree in immersion and in whose spirit the truth concerning the Essence of the Divine Being has developed, rise to the rank in which the One Who freely bestows gifts favors them with special gifts. At this rank the spirit severs its relation with all other than the Almighty and turns to the horizon that the appreciative heart has indicated. In the eyes of initiates honored with such a favor, the variations between the manifestations of the Divine Names disappear and everything seems to them manifested on the “screen” of the Divine Attributes and immersed in the lights of the Divine Essence. Seekers after the Ultimate Truth who, until they have attained to this rank, mention the Eternal One Who freely bestows gifts with His Names, such as the All- Beautiful, the All-Majestic, the All-Subtle, and the All-Overwhelming, take themselves into a life intoxicated with gifts that come directly from the Divine Being Himself, Who is the All-Light. They do not think to make any distinction between the Essence of the Divine Being and His manifestations.
To describe this state, Jalalu’d-Din Rumi, the most advanced one in intoxication, says:
O Muslims! I am unaware of myself: what means do you offer?
I am neither of the world, nor of the other world,
nor of Paradise nor of Hell;
neither am I of Adam nor of Eve,
nor of the highest abode of Paradise.
I am from nowhere and nowhere has no signs
with which to make me known.
I am divested of both body and soul,
being in the royal tent of the Beloved.
I have thrown away both my eyes,
seeing the two worlds together, and
I know only Him Who is the One, mention the One,
search for the One, read the One.
O Shams Tabrizi! I am so intoxicated in this world that
Nothing but intoxication can be a cure for me in this abode.
The third degree is the immersion in which signs suggest absorption. That is, an initiate may spiritually attain to the point beyond the sphere of the manifestations of the Divine Attributes and become immersed in the most sacred manifestation of the Essence of the Divine Being, Who is known as the First and the Last, the All-Outward and the All-Inward. This state is also viewed as a return to the station where the initiate’s heart recognizes the Almighty as a Hidden Treasure, or as a return to the unconditioned realm where everything pertaining to the created realm vanishes. A spirit which gets into this state usually expresses itself by saying: “There was God without there being anything that existed with Him. Now He is as He was before.”  It addresses itself to its confidants:
The place where I am has developed into no-space;
This body of mine has wholly become a soul;
God’s Sight has manifested Itself to me; and
I have seen myself intoxicated with His meeting.
It could not have been more beautiful for people of spiritual state and pleasure than in that stanza to express the relationship and difference between the Existence of the Self-Existent One and the portion of existence of all other beings, whose existence is totally dependent on Him. However, the following verses of ‘Abdu’r-Rahman Khalis are also truly beautiful:
O Muslims! What is this state in which I am and which bewilders me?
Sometimes I am a crazy lover, sometimes a wretched, insane one.
Sometimes I am a poor one having no place,
and sometimes the king of time.
For I am intoxicated with the wine of love, knowing nothing else.
I am one who pays no attention to the cap of austerity.
All praise and gratitude be to God that I have drunk the wine of love;
I am speaking in the land of Oneness the words of Him Who is One,
not worried that the king of this time may do anything to me,
and having no fear of those who wear coarse robes.
I have omitted the words that were uttered in the state of total intoxication as against the Book and the Sunna of the Messenger. Even though not to utter such words is a self-contradiction for the friends of God who are under the overwhelming influence of the spiritual state, the same action would mean straying from the path for those who are sober and can make a distinction between the Creator in His Transcendence and the created. It is especially heresy for common people to utter such words in mere imitation of those who have been overwhelmed by the spiritual state.
O God! O One Who guides the astray, guide us to the Straight Path, and bestow blessings and peace on him who is the most honorable of Your creation—Muhammad—and on his Family and Companions, rightly guided. Amen, O the All-Helping!