Sirius paused, talking with Harry was like going around in circles again and again and never getting anywhere. He could say the same thing again and again and Harry seemed to come up with the same reply each time. Sighing Sirius shrugged. "All magic changes you Harry. You would be a different person today if you had never learned to use magic at all. Life changes you. You can't live your life scared because you just might do something wrong - that's why you surround yourself with people you love, people who care about you and you trust that they'll keep you sane. It's a part of who we are, and no matter how we use it, magic will change us." He had no delusions about the dark arts, they were too prevalent in his family for him to have grown up with some idyllic picture of them in his mind. No he knew what they could do to a person if they let them, but he didn't think that James would end up going down that path.
"You don't see yourself the way others do." Sirius said finally, "You aren't just some man out to protect his family. People look to you for guidance especially now, hell even Dumbledore wants you on his side - do you think a man like that would want anyone who didn't have some sort of influence? What you say can and does make a difference to the people around you."
Sirius shrugged when Harry told him he hadn't asked about James' training. "He needs that right now, and when he feels like he can trust you not to tell him not to do certain things I think James will tell you about his training and all the things he has been learning. But he's safe, I can tell you that."