For if it is supposed that it is not necessary through itself, it must be necessarily entailed by what is necessary through itself. If it were not necessarily entailed by it, but could exist at one time and be nonexistent at another, there would be nothing necessitating its essence, nor would its essence be necessary through itself; hence it could not be beginninglessly eternal.

If it is necessarily entailed by what is necessary through itself, its nonexistence is impossible unless that which entails it ceases to exist. For a necessary consequence cannot cease to exist unless that which entails it ceases to exist. Yet the nonexistence of what is necessary through itself is impossible, so the nonexistence of its necessary consequence is also impossible. Whatever cannot be nonexistent does not admit the possibility of nonexistence.

If it is said:

Contingent things that have a beginning are necessary through another: when they exist, their existence is necessary by virtue of the necessity of their cause. Whatever Allah wills comes to be, and its existence is necessary; whatever He does not will does not come to be, and its existence is impossible. Their existence is impossible while they are nonexistent. Nevertheless, they admit both existence and nonexistence, and their nonexistence does not entail the nonexistence of the Necessary Being.

The reply is:

The distinction between the two is twofold. First, those things were nonexistent at one time and existent at another, so it is established that they admit both existence and nonexistence. Thus, it cannot be said that they do not admit