"Now this Lord is the Spirit and where the Spirit of the Lord is, there is freedom."
2 Corinthians 15:7
We often think of freedom as being able to do whatever we want to when we want to. While that is certainly one definition of freedom, that is not a freedom that will bring us peace or happiness. We have rules in society in order that all can co-exist peacefully. We willingly relinquish some of our freedom in order to be able to leave safe lives.
God sets up rules for us as well to help us lead good lives in the Spirit. By living lives rooted in love of God and love of neighbor; by following the Ten Commandments, we can obtain true freedom. Yes, sometimes it is hard. It can be easier to do the wrong thing rather than to go against the crowd and do what is right. It can be easier to give into temptation and do what "feels good" instead of what God tells us to do. Yes, we have free will and we can make those choices, but those choices won't set us free in the ways that matter. It is much easier to follow the Lord and make the right decisions and go to sleep with a clear conscience than it is to do the wrong thing and have to rationalize our actions and live with our guilt.