Hello Bahman,
the issue that is creating the confusion is the reality of time.
For the Christian:
It is interesting that science now is catching up to the claim that time is an illusion :
So when we talk about making decisions and things already being determined we have to take into the account that our perspective of time is not the same as others. It is especially not the same for God who is not bound by time and who has a clear view of all the choices we have made. The confusion arises when we try to stand in God’s shoes and bound Him as having the same experience of time as us.
Therefore with regards to our choices, we think since He knows NOW what it will be, and we don’t know NOW then we think that our choice is already determined.
But the error is bounding God’s sense of NOW to our own.
The movie MATRIX tried to deal with this question by putting the hero NEO bound by computer time with a figure not bound by computer time.
The person not bound by time knows the full reality but NEO thinks that takes away his choice. In the movie the Oracle (not bound by computer time) tries to tell Neo that it is completely his choice, to the oracle the choice has already been made by Neo.
The oracle sees the eternal NOW, but Neo is bound to experience lots of different Now’s as we do. The director tries to represent the coming together of the two different perspectives in time by NEO going trough a door.
Regards,
Abucs.