A.T. Robertson Commentary Romans 9:5

"whose are the fathers, and of whom is Christ as concerning the flesh, who is over all, God blessed for ever. Amen." — Romans 9:5 (ASV)

Of whom (εξ ων). Fourth relative clause and here with εξ and the ablative.

Christ (ο Χριστος). The Messiah.

As concerning the flesh (το κατα σαρκα). Accusative of general reference, "as to the according to the flesh." Paul limits the descent of Jesus from the Jews to his human side as he did in 1:3f.

Who is over all, God blessed for ever (ο ον επ παντων θεος ευλογητος). A clear statement of the deity of Christ following the remark about his humanity. This is the natural and the obvious way of punctuating the sentence. To make a full stop after σαρκα (or colon) and start a new sentence for the doxology is very abrupt and awkward. See Ac 20:28; Titus 2:13 for Paul's use of θεος applied to Jesus Christ.