Read Romans chapter 9.
In Romans 9:1-33 we see what seems to be a strict contradiction. We see God choosing who He will save. Then we see that the unsaved are unsaved due to their own blindness and arrogance. We are left wondering if there is a serious contradiction. How can God be completely responsible for something and we be held responsible as well?
This is something that I think we will all struggle to understanding. I found a great quote from our Sunday School binder that Tim Keller's church helped prepare.
"In (Romans 9) verses 6 to 29, Paul explains why anybody is saved... it is the sovereign election of God. In these verses (30-33) he is showing us why anybody is lost, and the explanation of that is their own responsibility... So this is what the Bible teaches. Election alone accounts for the saved, but non-election does not account for the lost... No one would be saved were it not that God in a sovereign manner has chosen him, as we have seen abundantly from verses 6 to 29. It is God's action alone that saves someone. So why is anybody lost? Is it because they are not elected? No! What accounts for the lost is their rejection of the gospel... We are not responsible for our acceptance of the Gospel, but we are responsible for our rejection of it."
He is the author of our salvation, but we are the authors of our damnation.
I just wanted to share that with you because it is the best response to the questions that Romans 9 brings up that I have ever heard.
Thank God for your salvation today.