'Slave' in the Bible

In Him the distinctions between Jew and Gentile, slave and free man, male and female, disappear; you are all one in Christ Jesus.

Now I say that so long as an heir is a child, he in no respect differs from a slave, although he is the owner of everything,

Therefore you are no longer a slave, but a son; and if a son, then an heir also through God's own act.