The heart is the chief source of defilement and impurity in God's sight. Our original sinfulness and natural inclination to evil are seldom sufficiently considered. The wickedness of people is often attributed to . . . bad examples, bad company, peculiar temptations, or the snares of the devil. It seems forgotten that everyone carries within him a fountain of wickedness. We need no bad company to teach us, and no devil to tempt us, in order to run into sin. We have within us the beginning of every sin under Heaven. We ought to remember this in the training and education of children. In all our management we must never forget that the seeds of all mischief and wickedness are in their hearts. It is not enough to keep boys and girls at home, and shut out every outward temptation. They carry within them a heart ready for any sin, and until that heart is changed they are not 'safe', whatever we do. When children do wrong, it is a common practice to lay all the blame on bad companions. But it is mere ignorance, blindness, and foolishness to do so. Bad companions are a great evil no doubt, and an evil to be avoided as much as possible. But no bad companion teaches a boy or girl half as much sin as their own hearts will suggest to them! The beginning of all wickedness is within! If parents were half as diligent in praying for their children's conversion as they are in keeping them from bad company, their children would turn out far better than they do.