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.
In the Bible, when a Hebrew had served another Hebrew as a servant for seven years he was allowed to go free. If at the end of the seven years the servant decided of his own free will that he loved his master and wanted to serve him for life, he would make a pledge or bond to stay and serve. The master would brand him in his ear with an aul. This servant could be called a "bond or branded slave": earmarked to serve his master.
"Galatians 6:17 - From henceforth let no man trouble me: for I bear in my body the marks of the Lord Jesus." When we get born again, we belong to God - we are His sons and daughters for eternity. When we of our own will decide to serve in the body of Christ, we become "branded servants" earmarked by the Lord Jesus Christ to serve.