lawful all things legality law without sin

I wanted to ask, what do you believe is the meaning of these passages by the apostle? 1 Corinthians 6:12, 1 Corinthians 10:23 Does this mean that there is no law against anything he does? How are "all things lawful" to him? At Romans 7:19 he talks about the "evil that he does": is the "evil...