Exodus 21:5–6 And if the servant shall plainly say, I love my master, my wife, and my children; I will not go out free: Then his master shall bring him unto the judges; he shall also bring him to the door, or unto the door post; and his master shall bore his ear through with an aul; and he shall serve him for ever.
The servant/master relationship here is not one of forced servitude and slavery but of indentured service due to debts. After six years, the indentured servant was free to go out. But he could also choose to stay. If the servant loved his master and wanted to stay, then he could willingly decide to stay and serve his master for the rest of his life. He would be marked in a way that all would know that he was a willing, life-time servant.
What a great picture of how we should serve the Lord. We owed a great debt. Christ sets us free. We are free to go and live our lives, but because of love and gratitude for what Christ has done for us, we decide to stay and serve Him the rest of our lives.
May love for Christ cause us to want to faithfully serve Him not out of duty but out of love for all He is and has done for us. 2 Corinthians 5:14 “For the love of Christ constraineth us; because we thus judge, that if one died for all, then were all dead:”