It seems to instruct physical circumcision too.
How could they spiritually circumcise someone in the verses below?
Woman can be circumcised under the new covenant. Woman could also be circumcised spiritually under the law. That may not compute with all people but it's true.
Here's what God told Abraham
Genesis 17:11 And ye shall circumcise the flesh of your foreskin; and it shall be a token of the covenant betwixt me and you.
This ritual was passed down from Abraham to Israel.
That was a religious rite to the Jews coming from Abraham. There is nothing in the law that says it began with Moses.
Here's what the Mosaic law says
Deuteronomy 10:16 Circumcise therefore the foreskin of your heart, and be no more stiffnecked .
Deuteronomy 30:6 And the LORD thy God will circumcise thine heart, and the heart of thy seed, to love the LORD thy God with all thine heart, and with all thy soul, that thou mayest live.
Here's what Paul says
Colossians 2:11 In whom also ye are circumcised with the circumcision made without hands, in putting off the body of the sins of the flesh by the circumcision of Christ:
This is what the seed of Abraham is
Romans 4:16 Therefore it is of faith, that it might be by grace; to the end the promise might be sure to all the seed; not to that only which is of the law, but to that also which is of the faith of Abraham; who is the father of us all,
Now this has everything to do with this verse.
Romans 1:16 For I am not ashamed of the gospel of Christ: for it is the power of God unto salvation to every one that believeth ; to the Jew first, and also to the Greek.
The next thing would be to address these verses
Romans 2:9-10
9 Tribulation and anguish, upon every soul of man that doeth evil, of the Jew first, and also of the Gentile;
10 But glory, honour, and peace, to every man that worketh good, to the Jew first, and also to the Gentile: