What?!
From Matthew Henry's Commentary:
That this privilege of being the children of God, and of being by baptism devoted to Christ, is now enjoyed in common by all real Christians. The law indeed made a difference between Jew and Greek, giving the Jews on many accounts the pre-eminence: that also made a difference betweenbond and free, master and servant, and between male and female, the males being circumcised. But it is not so now; they all stand on the same level, and are all one in Christ Jesus; as the one is not accepted on the account of any national or personal advantages he may enjoy above the other, so neither is the other rejected for the want of them; but all who sincerely believe on Christ, of what nation, or sex, or condition, soever they be, are accepted of him, and become the children of God through faith in him.