What does this Sar Naam stand for?

This Sar Nam is not an ordinary thing. Whole of the world is talking about Naam but none has any knowledge of this Sar Nam. Regarding it Sahib Kabir says—

Satya Shabad Satya Purush Jano.  
Naam Bina Sub Jhut Bakhano.  

Everything other than Sajeevan-Sar Naam is unreal and among the Naams it is the Sar Naam alone is Satya Purush Himself.
After their separation from Satya Purush, the Souls got entrapped in the prison of Niranjan. He didn’t let any of them escape to Amarlok. He tied the Jivas in the net of Sin and Merit. Reaping the reward of their sins or merits in hell or heaven, the Jivas began to wander in the cycle of 84 Lakh Yonis. In this mortal world, after suffering untold tortures in these 84 Lakh Yonis, the Jivas were given the human birth. However, even in this human birth too the Jivas were made to suffer much. This birth was, in fact, an opportunity for the Jiva to use it for attaining Permanent salvation. The Jivas could reach up to Niranjan alone. This is because there was none to impart them the knowledge about Amarlok. As such, no Jiva could reach Amarlok.
Niranjan began to eat all the Jivas after roasting them on a hot slab. He began to torture them in a variety of ways. Once, When Niranjan was busy in eating the Jivas , the latter cried aloud. They prayed in a body to God, if there is any, to save them from the tortures of Niranjan.
The painful cries of the Jivas crossed the seven skies and reached Param Purush. He understood everything. He called the Geyani Purush (Kabir Sahib) and telling him about the cruelties of Kaal Purush, asked him to go and save the Jivas from his clutches.

Ker Parnam Geyani Chaley, Karan Hans Ke Kaj  

Sahib Kabir offered salutations to Param Purush and decended to free the Jivas from the clutches of kaal Purush.
Sahib Kabir comes in to the world of Niranjan in every Yuga to free the Jivas. When he came to the universe for the first time (by the name ‘Satsukrit’), he remained there for one hundred years. Nevertheless, he failed to take any Jiva with him.
When Param Purush asked him the reason for not bringing any Jiva, he replied that one whom he made the idea clear in the morning, forgot all about it in the evening and one whom he made the idea clear in the evening, forgot about it in the morning. Then Param Purush handed over to him a hidden thing (Sajeevan Naam ) saying Kaal will be unable to exercise any influence on one who would get blessed with it.

---