Matthew Poole and continuators on Galatians 4:1

NOw I say, that the heir so long as he is a child, differeth nothing from a servant, though he be Lord of all .

The Apostle had before determined, that the whole body of such as believed in Jesus Christ, were that seed of Abraham to which the promise was made; and so Heirs of the promises made to him; yet so that as it is among men, though a child be a great Heir, and Lord of a great Estate, yet while he is under age, he is used like a Servant; so the time of the Law being as it were the time of Believers non-age, those who lived in that time were used like Servants.