'Slave' in the Bible

For am I now making an appeal to people or [to] God? Or am I seeking to please people? If I were still trying to please people, I would not be a slave of Christ.

There is neither Jew nor Greek, there is neither slave nor free, there is neither male and female, for you are all one in Christ Jesus.

Now I say, for as long a time [as] the heir is a child, [he is] no different from a slave, [although he] is master of everything,

so that you are no longer a slave but a son, and if a son, also an heir through God.

For it is written that Abraham had two sons, one by the female slave and one by the free woman.

But the one by the female slave was born according to human descent, and the one by the free woman through the promise,

Now Hagar is Mount Sinai in Arabia, and corresponds to the present Jerusalem, for she is a slave with her children.

But what does the scripture say? "Drive out the female slave and her son, for the son of the female slave will never inherit with the son" of the free woman.

Therefore, brothers, we are not children of the female slave but of the free woman.