God won't. We leave Him, however, sometimes permanently.
Dear Kosta, if God will never leave us, and he will never forsake us, we cannot leave him. If God calls us as his children, he will never lose us. Ever. If God were to lose even one of his children, he would be a failure, and God isn’t a failure, is he? Just like the parable of the lost sheep, God will continue the search until the lost sheep is found.
If God has called you his child, is your will stronger than his? You say you have free will, I say if you can twart God, your will is stronger than his, therefore you are HIS god. Is that the way it is?