A slave is not a permanent member of the family, but a son belongs to it forever.
Ὁ δὲ δοῦλος οὐ μένει ἐν τῇ οἰκίᾳ εἰς τὸν αἰῶνα· ὁ υἱὸς μένει εἰς τὸν αἰῶνα.