One thing about the law of liberty is that you have a choice or free will. The opposite of freedom is bondage. When someone is in bondage, there is no free will or choice involved. Bondage is enslavement. When you feel obligated to do something you don’t have to do, then you are in bondage to it, such as sin. When a sinner gives his/her life to Christ, the power of sin is broken over their lives. But they still have a choice to either sin or walk in freedom. The power or influence that sin has on an individual that doesn’t know Christ is not the same as someone that does know Him in the pardon their sins. They are free from sin.
Paul in his letter to the Corinthian Church said that he is free to do whatever he wants, but it is not always proper to do what he wants to do. All things are lawful unto me, but all things are not expedient: all things are lawful for me, but I will not be brought under the power of any. (1 Corinthians 6:12 KJV) He said he will not be brought under the power or influence of anything or anyone. Walking in your new found freedom in Christ is to choose not to sin and to follow Him whole heartily.