William Burton Pope said this quote

“ In the secret recesses of man's nature the grace is given disposing and enabling him to yield. Though the will must at last act from its own resources and deliberate impulse, it is influenced through the feeling and the understanding in such a manner as to give it strength. It is utterly hopeless to penetrate this mystery: it is the secret between God's Spirit and man's agency. There is a Divine operation which works the desire and acts in such a manner as not to interfere with the natural freedom of the will. The man determines himself, through Divine grace, to salvation: never so free as when swayed by grace. ”