The verb “serving” means: to act or conduct oneself as one in total service to another, perform the duties of a slave. BDAG The root of this word literally comes from the noun translated slave. The word slave has a sharp, humiliating edge to it in American English. The word “Lord” means: one who is in charge by virtue of possession. BDAG
We find warmth in saying, “Jesus is my Lord.” But it may be a bit more difficult to confess the other side of that coin: “I am a slave of Jesus Christ.” During the late days of slavery in the western world, when missionaries were prevented from entering some slaving regions, there were missionaries who sold themselves into slavery to carry the Gospel to the slaves. They committed to this slavery in obedience as slaves to their true Lord and Master who had served them in the same fashion. Jesus came into this world in “the form of a servant” and “humbled himself, and became obedient unto death, even the death of the cross.” Philippians 2:7,8
Based on Romans 12:11 we are to be energetic, committed, thoughtful slaves. We can't be productive if we are the kind of sullen slave who is constantly dreaming of freedom from our Master. Our allegiance to Jesus as our Master is deep and personal, and it is vital to our spiritual growth.
There is no practical sanctification outside of slavery to Jesus. There are personal commitments that He may individually require of each of His slaves, and then there are collective obligations that He places upon every member of His church. Let us be His faithful slaves, He deserves nothing less from His blood bought people.