“We know that in everything God works for good with those who love him, who are called according to his purpose.” (Romans 8:28)
St. John Chrysostom presents an interesting picture of the relationship between God’s will and our free will.
“God does not compel, but allows people to be masters of their own choices even after the call.” (Margaret M. Mitchell, The Heavenly Trumpet, p 213)
God calls us to follow Him and to obey Him, but even when the omnipotent God calls us, God allows us to choose how to respond. There is a true synergy between God and any human – we have to cooperate with God for our salvation.
“… work out your own salvation with fear and trembling; for God is at work in you, both to will and to work for his good pleasure.” (Philippians 2:12-13)