The Sufi path is one's quest for Maarifat i.e. knowledge of Allah ﷻ, the divine knowledge gained spiritually which is disclosed to the hearts that carry thirst for it and are prepared to struggle and are patient enough to be gifted. It is not an easy path as Prophet Musa (alaihi salaam) would not have said the following words in his quest of this knowledge to reach and learn from the Mystic Khidr (alaihi salaam): (Al Quran 18:60) "…I will not cease [traveling] until I reach the junction of the two seas or continue for a long period."
The Sufi path is compared to the path of Musa (alaihi salaam) which might "continue for a long period" which indicates struggle and intense traveling. The resolve required to travel and reach the destination should be the same as expressed in his words "I will not cease (traveling)" regardless of difficulties. The destination of the Sufi path is the "junction of the 2 seas" which represents 2 oceans of knowledge i.e. external knowledge and internal knowledge. The external knowledge is the outer aspects of Islam which are extremely important to adhere to before you go further on your journey. The junction where Musa (alaihi salaam) struggled to reach was the point from where one can gain access to internal knowledge which is gained spiritually referred to as Maarifat - spiritual divine knowledge that brings one closer to Allah ﷻ, whereas the highest stage of attaining such knowledge is called ilme laduni (also referred to as divine knowledge) or ilhaam (inspiration) experienced by mystics such as Khidr (alaihi salaam).
The purpose of our existence is to know Allah ﷻ and establish a strong spiritual connection with Him at all times and that is the foundation of Sufi path. Any uncertainties, misinterpretations, innovations on this path can weaken our spiritual connection with Allah ﷻ and prevent us from His Maarifat. It is actually through Maarifat that we continue to come closer to Him. The most difficult obstacle of this path is our own Nafs (evil commanding soul) and it is due to this reason the blessed Prophet Muhammad ﷺ compared striving against it as greater than fighting an enemy in a battle:
“You have come for the best, from the smaller jihad (al-jihad al-asghar) to the greater jihad (al-jihad al-akbar).” Someone said, “What is the greater jihad?” He said: “The servant’s struggle against his lust (evil self).” (Al Bayhaqi) The one who can overpower their Nafs succeeds in crossing the "junction of the 2 seas" and it is due to this reason Prophetic saying usually quoted in Sufi circles is: “He who knows his own Nafs has known his Lord” (Hadith) The Nafs is the bridge that connects the 2 seas and crossing over should be the primary focus and purpose in this path.
Therefore this path is difficult and had it not been difficult the people of this path (i.e. Sufis) would not have been the strongest in their obedience and love for Allah ﷻ and His Messenger ﷺ. Anyone who initiates to travel on this path can not travel alone due to it being difficult. They need a spiritual guide in addition to one’s own learning and practicing, just like Musa (alaihi salaam) required the mystic Khidr (alaihi salaam) for his journey ahead. One of the famous Sufis Abu Ali Daqqaq (r.a) gave the example of a novice traveler to a plant which if it grows on its own will have defects but if its taken care by a gardener its growth will be much better, it will also give flowers and fruits. We are the plants, the spiritual Imams are the gardeners, the process is long and difficult but not impossible.
Please also read: Is Tasawwuf a Bid'ah (Innovation) in Islam?
Muhyiddin Ibn 'Arabi
Documentation of the Hadith of Jihad al-akbar (Greater Jihad)