Bond Servants

The Bible describes a time where slaves, even though they had no rights, they had one - they had the right to leave their master after they worked off their indebtedness.

However, if out of love for this master they chose, of their own free will, to stay and become a life long member of that home, they went through a strange and agonizing ceremony. 

The master would literally nail the ear lobe to the doorpost of the house with a hammer and a small spike.  The spike or awl was immediately removed but the ear hole and scar remained as a symbol of their commitment.  It was a sign like a wedding ring - only more demanding.