“Those who cling to worthless idols forfeit the grace that could be theirs.- Ps 119:8
The assumption is that if you are not serving God, you are serving something else. If you are not a slave to the spiritual authority of God, you are under the spiritual authority of something else already. The opposite of Christianity isn't atheism. It's Idolatry.
Euripides, the greek tragedy writer:
"No one is truly free, they are a slave to wealth, fortune, the law, or other people restraining them from acting according to their will."
What is astounding here is this Psalmist is NOT saying, I gave up my freedom to serve you, he says, I now walk at liberty because I sought your precepts. I'm free BECAUSE I'm your servant. I used to be a slave to fear. Because there were certain things I thought I had to have. I used to be a slave to resentment, because I thought there were certain things I had to have. I used to be a slave to guilt. I could never measure up. But now that you are my master, nothing else masters me. Now that I serve you, nothing else orders me around. I can come and I can go. I have choices - finally!
Here's the point: Freedom is not a lack of restrictions. Freedom is finding the right restrictions. Restrictions that fit your being.