How is Spiritual Influence Transmitted?
GOD draws unto Himself everyone who is willing, and guides to Himself everyone who turns to Him. (Quran, 42, 13)
One of the conditions required for calling men to God with clarity, is to sow in them the seed of spiritual life, and to be authorized by a living
spiritual guide to teach the rules of Sufism and to transmit initiation. 
In accordance with the rules of the Muhammadan way, the true educator of souls (murrabi) is a master authorized (mudhun) to lead and orientate all those who commit themselves to this way, which is purification from the faults of the soul, embellishment of noble qualities and arrival at the station of excellence (maqam al-ihsan).
This authorization (idhn) is indispensable for transmitting spiritual education (tarbiyya), just as it was imperative in the past for those who taught religious sciences to have received the permission (ijaza) from the scientists with whom they had studied exoteric sciences.
to Sufi masters, spiritual authority not only bears witness to the aptitude for guidance, (irshad), and the qualities (akhlaq) on which the capacity to guide is based, but above all, it is thanks to the virtue of this authorization that spiritual influx (baraka) and spiritual practices bear their fruits and awaken the hearts of those who aspire. Also, all those who receive the authorization to preach to men remembrance of God (dhikr) and are the revivers of this religion receive clear signs from their Lord
. (Quran, 6, 57).
Continuation of the Way of Initiation
An essential point must be made clear. One must not think, according to an opinion current in our time, that there can be no more qualified and authorized spiritual guides. Indeed,
whatever the state of spiritual degeneracy of the world today, the deviations or the deceptions that one notices, or the particular conditions of life in our time, the search of all those whose hearts are brought to life by an ardent desire for knowledge cannot remain unanswered.
In other words, at no point in the history of humanity can spiritual guidance, which manifests itself through the meeting with a fulfilled and authorized master, be lacking. Otherwise, it is an affirmation not only that the possibility of the way of initiation does not exist, but more seriously still, that guidance (hidaya) and divine mercy have abandoned humanity, which is quite simply absurd. Imam Qushayri said that as long as Islam lasts there is no time in history when there would be no masters. 
Similarly a famous hagiographic work  quotes the different versions of a prophetic hadith which clearly indicates the permanence of the presence of men of God in our world.
In one of these versions reported by Muslim, according to the companion Saad ibn Abi Waqas, the Messenger of God said: The people of the Maghreb will not cease to know the truth until the Hour comes.
According to Saad ibn al-Malik, the Messenger said: The people of the West (gharb) will not cease to know the truth until the day of Resurrection.
Finally, according to another tradition from the same companion: A group of my community will not cease to be in the truth in the Maghreb
until the Hour comes.
If the way cannot fail to manifest itself to those who have a real inner quest, we should point out another prejudice according to which everyone with eminent spiritual qualifications, or having a high degree of spiritual realization, has the ability to guide.
In reality, as we said above, only someone who has received spiritual authority from a living master can guide men. And it is actually by virtue of this that it becomes possible for him to educate souls and to purify hearts, that is, to transmit this science of spiritual education which is, according to the Sufi masters, a science of the spirit, a science of inspiration which is a thing neither written nor learnt. It is also on this authority that the regularity of the chain of
initiation (silsila) rests a chain that goes back to the Messenger of God through an uninterrupted line of masters. Whoever has not received this authorization from his master, himself authorized, cannot be mentioned in a chain of initiation, for he has no right to the title of shaykh and everything that he transmits remains sterile like seed sown on stone.
This is why the function of spiritual guide depends essentially on divine election, on a divine order (amr ilahi) that Sufis also refer to by the term divine authorization (idhn rabbani). 
Free will and divine freedom
Abu Abbas al-Mursi said: No master manifests himself to his disciples if he has not been
determined by his inspirations (waridat) and if he has not received an authorization from God and His Messenger. It is by the blessing (Baraka) of this authorization and the secret power that it implies, that our cause is sustained and that the state of his disciples is protected. 
It is therefore by the mercy of this authorization that the master receives the trust of the divine secret (sirr) and it is by its power that he acquires the capacity to leave spiritual descendants. The efficiency of the richness of the divine secret only transforms people by the virtue of this authorization which invigorates faith and constantly renews the propagation of the Muhammadan light in the hearts of those who aspire. What the disciple receives when he commits himself through the initiatory pact, which marks his entry into the way, is comparable to a seed sown which may
grow thanks to the spiritual direction of the authorized master.
Moreover, in a way this authorization has an effect on the disciple who, when he obeys his master and follows his indications, submits himself at the same time to the Lord. In fact, the disciple who trusts in his guide participates in the authorization of the latter by virtue of the fact that he himself is authorized to apply himself to divine invocation (dhikr) as well as to other spiritual practices. He benefits in this way from the presence and the blessing influence of his guide.
This is why the disciple who asks the advice and permission of his master for all the decisions and the resolutions that he is led to make in his life, will see all his states, all his movements and his acts become an invocation, that is
to say, a way of worshipping the Lord. He will thus become one of those who is faithful to the pact and he will be amongst the spiritual beings nourished by divine light, whom no veil separates from what is hidden in the invisible world; and by the spiritual power of his invocation, he will be saved from the negligence and the futilities of this world.
Let us take the specific example of individual will which is, according to Ibn Ajiba, one of the veils and one of the shadows that the Lord has placed over the heart of the servant; for it is the will which is at the root of the desire to assert oneself and of the thirst for control inherent in the human soul and that each of us personally feels.
Only turning to a teaching master allows the disciple to distance himself and
gradually break away from his individual willpower and his free will (ikhtiyar).
For that is a matter of a veil which creates the illusion, so that man imagines that he is totally free to act and choose as he pleases. Whereas the one, who submits to his guide and turns to him in everything and in all circumstances, will then see this veil gradually lift until he receives the mercy of the understanding of the heart which leads him to realize that only God is the real agent of everything.
But that does not in the least come from a theoretical knowledge, but rather from inner experience and inner tasting (dhawq). This is why the disciple must think that everything in his master that may appear to him to be individual willpower and free will, is however a manifestation which
comes from God and leads to God, and this is a condition of benefiting from this divine authorization and the real means for whoever wants to follow the path of servitude, one of the aspects of which is none other than giving up ones own willpower.
It is therefore an immense favour to meet one of the saints of God and to receive from him the authorization to follow this noble way. It is what Ibn Ata Llah taught in one of his wisdoms: Exalted be He who does not manifest His saints but to manifest Himself, and Who only leads to them those that He wants to lead to Him.
Idhn is given by a
living master to one or several of his disciples: the person who receives the idhn from his master should then have inner confirmation of it.
There are several kinds of idhn:
Universal or partial: the master is authorized to guide all those who ask him for it (universal), or a limited number of people meeting certain conditions (partial).
Absolute or conditional: the master can lead to the end of the path (absolute), or can simply lead his disciples to a certain spiritual degree (conditional).
Total or limited: the master can hold the spiritual secret of all the divine Names, which he can transmit (total idhn), or of a limited number.
In all cases, the individual willpower of the shaykh does not play any part at all: he receives this idhn and communicates it to the disciples concerned.
Every authentic Sufi way must, in this way from idhn to idhn, go back to the Prophet Muhammad, through a chain of initiation: the silsilla.
 Abd alQadir Isa mentions in his work haqaiq an al-tasawwuf the truth about Sufism, 5th edition, Allepo, 1993, p.78; four conditions for guiding men to God:
> being aware of the arena of obligations (faraid)
> being a knower by Allah
> knowing the methods of purification of souls and of spiritual education
> being authorized by his spiritual guide (shaykh)
 Quoted by Chodkiewicz in The Spiritual Masters in Islam, Knowledge of the Religions, No 53-54, 1998.
class=MsoNormal> Ibn Ziyyat, Tashawwuf ila rijal tasawwuf. A look at the time of Sufis, life of the Muslim saints of southern Morocco of the 5th, 6th, and 7th centuries of the hijra; Arabic text arranged, annotated and presented by Ahmed Toufiq: translated from the Arabic by Maurice de Feynol. Ed. EDDIF & UNESCO, 1995.
 La Voie Soufie, Faouzi Skali, Albin Michel, 1985, page 160.
 See about this saint « Wisdom of the Sufi Masters » by Ibn Ata Allah, translation and annotations by Eric Geoffrey, Grasset.
 Two treatises on the unity of existence, Ibn Ajiba,
Arabic text arranged, translated and presented by Jean-Louis Michon, al quobra zarqua, Casablanca, 1998.
by Daniel Roussange