Galatians 3:7

Γινώσκετε : Ye perceive. The emphatic admonition, Know ye, adopted in our versions, would require an aorist imperative γνῶτε, as in Hebrews 8:11. This verse contains a deduction from the former, as is suggested by the inferential ἄρα. Since faith was the ground of Abraham's justification, it follows that those who inherit his faith are his true sons. οἱ ἐκ πίστεως, sc. υἱοὶ ὄντες. The form of the Greek sentence suggests the insertion of these words to complete the ellipsis. With this addition the verse carries on the previous argument to its natural sequel. The faith of Abraham was there declared to be a fundamental condition of the divine acceptance. Those therefore who inherit his faith are his sons indeed and heirs of his blessing. The discourse of Christ recorded in the Gospel follows the same line of argument: If ye were Abraham's children, ye would do the works of Abraham (John 8:39). Both alike urge that resemblance in life and character is the true test of sonship. Gentiles therefore who prove themselves sons of Abraham by exhibiting like faith are his sons indeed, and inherit the blessing promised to his seed. The antithesis in Galatians 3:10, ὅσοι ἐξ ἔργων νόμου εἰσίν, sc. υἱοί, presents a like ellipsis: the exclusive claim of Jews to be sons of Abraham in virtue of their observance of the Law is there disposed of on corresponding grounds.