This is because] (1) if one of (2) the shared and the particular elements is an accident [of the other, it would follow that necessity is an accident] (3) of the Necessary Existent or a substratum for it. On either assumption, necessity (4) would not be an inseparable attribute of the Necessary Existent. This is impossible, since the Necessary Existent cannot possibly be anything other than necessary.
If, however, one is an inseparable concomitant of the other, the shared element cannot be the cause of the particular element, because wherever a cause exists, its effect exists. It would then follow that wherever the shared element exists, [the particular and shared elements would exist] (5) in each of the two. Consequently, what is particular to either would be present in both, as would what is particular to the other. This is impossible, for it abolishes the very distinction between them.
This summarizes what Ibn Sīnā set forth in his Ishārāt (6), together with the commentators on the Ishārāt, such as al-Rāzī (7), al-Tūsī (8), and others.
These two arguments summarize what was set forth by al-Fārābī (9), al-Suhrawardī (10), and others among the