A Christian is completely free, subject to nothing and no one;
A Christian is a dutiful servant, subject to everyone. -Martin Luther

At first, it seems contradictory, that you’re completely free but at the same time a dutiful servant. But it really is a way to express what the Bible teaches about the Gospel of the Lord Jesus Christ.

Christ has set you free from all of God's Laws, and Commandments, and requirements for holiness, righteousness, and perfection. Because of Jesus, you are now declared to be perfect, holy, and righteous because Jesus was perfect, holy, and righteous for you and in your place!

Ironically, your freedom means that you are a servant: loving, helping, and serving your neighbor! Your freedom means that you a free to glorify God, love your neighbor, and grow in faith! You do not need to use your good works to appease God; rather you are free to use your good works to love and help your neighbor. Luther would later even say that God does not need your good works, but your neighbor does! And so we live our perfectly free lives serving others, helping others, loving others.