An Unknown Meaning of the word " Āz" in " Rostam and Sohrāb Story"

The above line is one of disputable and difficult lines in the introduction of “Rostam and Sohrāb Story”. There are several suggested meanings for the lines and the phrse "door of āz" including death, greed and the supreme greed of humanity for knowing secrets of death to achieve immortality. The author reasons that the following meanings can be suggested for the word for āz: "need, requirement, wish and in general human natural demands”. Accordingly, the meaning of this line is as follows: “all human beings have natural demands like eating, drinking, sexuality and various wishes which are characteristics of the life in this world”. Since this life with its own specific features is in contrast with death, the mysterious door of death will be opened to nobody.