Then he turned to his saying, "Indeed, I have become weak" [Maryam: 4], and his saying, "And indeed, I feared the relatives". This means the actions of the relatives that they would mismanage the succession "from behind me", meaning in some time after my death. "And my wife is barren", she does not give birth [originally - as indicated by the action of existence -]. "So grant me", meaning let it be caused - due to my old age and weakness and Your response [to me -] with an answer, and my fear of the bad management of my relatives, and my despair regarding the child is customary due to my wife's barrenness, and my reaching an age limit where there is no movement with it - that I say to You, O Able One over all things: Grant me "from Yourself", meaning from the hidden matters that are astonishing which are with You, You have not made them follow the paths of habits and continuous causes, not from a cause that I know, for the causes of that are nonexistent for me.

And there has already been further clarification of this in [Aal 'Imran] regarding the meaning of "a guardian" [meaning -] from my loins, indicated by "descendants" in the other surah.