Spiritual legacy and righteous heirs

وَإِنِّى خِفْتُ ٱلْمَوَٰلِىَ مِن وَرَآءِى وَكَانَتِ ٱمْرَأَتِى عَاقِرًا فَهَبْ لِى مِن لَّدُنكَ وَلِيًّا

And indeed, I fear the successors after me, and my wife has been barren, so give me from Yourself an heir