The reason for calling it sefer (journey) is that it reveals people's character traits. (Luma, 252)
Sefer is divided into two types: bodily sefer is the transition from one region to another. Sefer with the qalb (the heart) is the ascent from one attribute to another. You see thousands who journey with their bodies, but those who journey with their qalb are very few.
When Ruwaym was asked about the etiquette of sefer, he replied: Sefer is when your thought does not surpass the step you take, and the place where your qalb stands becomes your station. (Qushayri, 142)
The aim of sefer is, first and foremost, to distance oneself from familiar things, to strip the nafs (the lower self) from what it is accustomed to and knows, to remove what it trusts and relies upon, and to burden the nafs by making it taste the pain of separation from friends, family, and homeland. Whoever, thinking of the reward with Allah, patiently endures being separated from loved ones and habits, and refrains from things they enjoy, attains great virtue... The aim of sefer is to unravel the subtleties of the nafs and to bring forth its ego and claims. For without sefer, it is almost impossible for these to become manifest. The reason it is called sefer is that it reveals character traits. Once the illness is known, its treatment can be sought.
Sefer is as effective on the nafs of the beginner (the one who enters the spiritual path) as acts of worship such as prayer, fasting, tahajjud, and similar supererogatory devotions. One who is engaged in supererogatory worship is one who journeys from the stations of heedlessness to the stations of nearness to Allah the Exalted. The true traveler (musāfir), with a good intention for the sefer-i fitri (innate journey) that Allah the Exalted has granted, opposes his desires, migrates from the pleasures of the dunya (world), and journeys toward Allah, traversing distances and crossing thirsty deserts.
The aim of sefer is to see the lessons and traces of the past, to look reflectively at things that are subjects for contemplation, to closely examine the earth, the mountains, and the regions trodden by people, to listen to the tasbih (glorification) of inanimate things, and to understand what the surrounding beings say with their lisān (language) of state. Through witnessing lessons and ishārāt (spiritual indications), the state of yaqaza (wakefulness) is renewed. Reviewing the places visited helps increase the number of proofs and witnesses.
Sefer consists of journeying with the qalb. For the journey of turning toward the Real (God) begins with dhikr (remembrance of God). (Istilah, 530)
Sefer is the ḥāl (spiritual state) of the musāfir (traveler). Tariq is the path walked within. This path is traversed through transactions, maqām (spiritual stations), ḥāl (spiritual states), and maʿrifa (gnosis, experiential knowledge of God). For sefer depends on these: maʿrifa, ḥāl, and the musāfir's (traveler's) journeying from his own character traits, the levels of the world, the levels of the Divine Names, and ḥaqīqa (inner realities). For this reason, sefer is proper to the qalb (it is done with the heart). (Futūḥāt, II, 378)
Sefer is the turning of the qalb toward the Real (God). Sefer is of four kinds: The first is sayr ilāllāh (journeying toward Allah). This is reaching the clear horizon (ufq-i mubīn) from the levels of the nafs (being freed from all the turbidity of the nafs). The end of the station of the qalb is the beginning of the manifestations related to the Divine Names.
The second is sayr fillāh (journeying in Allah). It is being characterized by His attributes, and the realization of His Names at the highest horizon (ufq-i aʿlā). This is the end of the station of aḥadiyya (Divine Oneness).
The third is the ascent to the ayn al-jamʿ and the station of aḥadiyya. This is the station of kāba qawsayn (the station beyond duality). When one ascends, it becomes a station; when one descends, it is the end of walāya (sainthood).
The fourth is sayr billāh ʿanillāh (journeying from Allah with Allah) to attain kamāl (perfection). This is baqāʾ (subsistence in God) after fanāʾ (annihilation in God); the station of distinction after union. (Kāshānī, 103; Jāmiʿ, 86)
Sefer is a means to escape from what is fled or to attain what is desired. Sefer is of two kinds: bodily sefer from one's homeland, and sefer with the qalb from the lowest of the low to the malakūt (spiritual realm) of the heavens. This is the highest sefer. Those who remain in the state in which they were raised after their birth, who are ossified by taqlīd (imitation) of their fathers and remain at a deficient level, who are content with the station of deficiency, have preferred to expand the earth rather than the heavens. Yet the earth is the darkness of prison and the constriction of captivity. (Qudāma, 116)