‘Vilayate-Takvin’ (authority over creation) implies that Imam (Allah’s Hujjat) plays a fundamental role in creation. Just like the sun, which plays a vital role in giving material bounties to living creatures, Imam (a.t.f.s.) receives the blessings of existence with all its perfections, from the divine world, and bestows it to all other creatures.
Considering that the blessing of existence and its perfections descends from top to bottom, the Almighty Allah bestows this bounty by means of superior and noblest creature down to the other creatures. In the traditions of immaculate Imams (a.s.), we read:
“If the earth is devoid of an Imam, it would swallow its inhabitants.” 
“The existence of ‘Hujjat’ (Imam) is a must before the creation, with creation as well as after creation.” 
As per substantial and sound traditions concerning the manner of creation, the Almighty Allah, in the preceding world created the light of holy prophet (s.a.w.a.) from His own magnificence light. Then, from the holy prophet’s light, He created the light of Amir-ul-Mu’mineen and Fatemah (a.s.). Thereafter, from the light of these two figures, He created the light of Imam Hasan and Imam Husain (a.s.) and later the other Imams (a.s.). The illuminating light of immaculate ones (a.s.), the first of its stages in creation, started glorifying and praising the Almighty Allah. Then, in the world of spirits, their pure souls were created and after formation of the world of body, the soul got attached to body and their elemental bodies were formed. Thereafter, from their light, the Almighty Allah manifested the rest of creation.
It’s interesting to point out that there exist a general resemblance between their bodies and the souls of Shias. Their bodies are from the world of“Elliyeen” and their souls higher than“Elliyeen” . On the other hand, the souls of Shias are from the world of“Elliyeen” and their bodies from a lower world.
Thus, medium of blessing via Hazrat Mahdi (a.t.f.s.) implies receiving the ‘light of existence’ from higher levels and giving it to the lower levels i.e., transfer of blessing of existence to lower creatures. Such type of creation is something in accordance with Divine Wisdom and Allah has made it a custom in all His creations. In philosophical terms, this type of creation (which is certain and conclusive as per traditions) is named as the principle of ‘Emkan-e-Al-ashraf’o-Fal-Ashraf’ Those interested for a detailed account can refer to books on traditions in the chapter related to creation of light of holy prophet (s.a.w.a.) and Imams (a.s.).
Some of the benefits of Imam’s existence during major concealment are like the benefits of the sun concealed behind the cloud. As per narration in Bihar-ul-Anwar narrated from Muhammad-ibn-Ya’qub Kulaini, Hazrat Mahdi (a.t.f.s.) himself says:
“The manner one benefits from my existence (my place in creation and society) during the concealment era is like the manner one benefits from the sun concealed behind the cloud. Verily, I am a respite and comfort for the inhabitants on earth just as the stars are for the inhabitants in heaven…..” 
Jabir-ibn-Abdullah Ansari inquired the holy prophet (s.a.w.a.): ‘Will the Shias benefit during concealment of the ‘Qaem’? The holy prophet (s.a.w.a.) replied:
“Yes, I swear by the One who appointed me as prophet that they shall derive benefit from him and will find brightness from the light of his ‘Vilayat’ just as they benefit from the sun that is hidden behind the clouds.” 
Under this tradition, Allama Majlisi has described eight aspects of similarity between benefits derived from Imams during concealment and sun hidden behind clouds. We have explained them in detail in the book ‘Mehre-Mahboob’ and all of these are discussed from the viewpoint of creation and existence.
But from the viewpoint of divine legislation and guidance and bid for good and forbid of evil, Imam is the protector of religion, guide for mankind, very sympathetic, a compassionate father for them, a radiant sun emitting life and a pleasant limpid ocean.
Imam is the model of servitude before Allah and the caravan leader of worshippers and devout people taking mankind towards the desired divine goal.
This level of guidance, showing the way, is related to divine guidance (Hedayat’e-tashri’ee). Rather, it makes one reach the desired perfection which is named as ‘esoteric guidance in creation’ (Hedayat’e-takvin)
In invocations we say:
“ آللهم إني اسالك بحق محمد و علي و فاطمة و الحسن و الحسين
The reason we swear by their names before Allah is because they are the medium of elevation of our deeds and prayers to the Divine threshold. For this reason, Imam Reza (a.s.), while describing the position and rank of Imamate says in a tradition come down in Kafi as follows:
“Completion of prayers, zakat, haj and……….is by means of Imam” (belief in Imamate)