No man can be freed from sin except by grace, and yet the sinner is to be blamed if he is not converted.
 Bertrand Russell, A History of Western Philosophy (1945). copy citation

Context

“He then passes on to sin, predestination, and election, on which his view is broadly that of Augustine. By mortal sin a man forfeits his last end to all eternity, and therefore eternal punishment is his due. No man can be freed from sin except by grace, and yet the sinner is to be blamed if he is not converted. Man needs grace to persevere in good, but no one can merit divine assistance. God is not the cause of sinning, but some He leaves in sin, while others He delivers from it. As regards predestination, Saint Thomas seems to hold, withy Saint Augustine, that no reason can be given why some are elected and go to heaven, while others are left reprobate and go to hell.” source