Galatians 4:1

I mean this: As long as the heir is a minor, he is no better than a slave, although he is the owner of all the property,

Galatians 4:23

But the child of the slave-girl was born in the ordinary course of nature, while the child of the free woman was born in fulfilment of the promise.

Galatians 4:29

But just as then the child born in the ordinary course of nature persecuted the one born through the influence of the Spirit, so it is today.

Treasury of Scripture Knowledge

Summary

Now I say, That the heir, as long as he is a child, differeth nothing from a servant, though he be lord of all;

Bible References

That

Galatians 4:23
But the child of the slave-girl was born in the ordinary course of nature, while the child of the free woman was born in fulfilment of the promise.