Jn. 8:35 And the slave does not abide in the house forever; the son does abide forever.

约八35奴仆不永远住在家里，儿子是永远住在家里。

youdao

So you are no longer a slave, but a son; and since you are a son, God has made you also an heir.

可见，从此以后，你不是奴仆，乃是儿子了。既是儿子，就靠着神为后嗣。

youdao

And the sultan himself was, in theory, a slave as well, because he was the son, most often, of his father, plus a woman out of the harem who was, in theory, a slave.

NPR: The History of Political Succession