Following quotation on the existence of God

[Qasim_Husayn]

Salam can you explain the following quote from allamah tabatabai:

"The universe is temporal (in constant change and movement) and each particular part of it can become nonexistent. Therefore, it (the particulars) are not the existence that cannot be made nonexistent. This world depends on a reality which cannot be made nonexistent and it is in the light of that reality that the world becomes existent. If that reality did not existent, this world and whatever in it would not have existed. Of course, it does not mean that the reality unites with the thing in a way such that they become one thing. It does not permeate or indwell in them either or that a part of the reality separates and joins things; in fact, it is like light with which dark objects become bright and without which they remain dark."

How does cosntant change and movmenet mean that things become non-existence, if I throw a ball, how does the change of ball make stuff go from existence to non-existence. 

"Therefore, it (the particulars) are not the existence that cannot be made nonexistent."

If they can't become non-existant then why did you say particular parts of it become non-existent

"This world depends on a reality which cannot be made nonexistent and it is in the light of that reality that the world becomes existent. If that reality did not existent, this world and whatever in it would not have existed."

How did he reach that conclusion