'Bond servant' in the Bible

Wast thou called being a bondservant? Care not for it: nay, even if thou canst become free, use it rather.

For he that was called in the Lord being a bondservant, is the Lord's freedman: likewise he that was called being free, is Christ's bondservant.

For though I am free from all men, I have made myself a slave to everyone, so that I may win more [for Christ].