Romans 9:8

8. That is The apostle now reads into the literal words In Isaac shall thy seed be called their higher spiritual import.

Children of the flesh… of God… of the promise This threefold classification of children must be carefully analyzed. Children of the flesh does not mean, as Barnes defines it, merely “the natural descendants;” but all are children of the flesh who depend upon the flesh, that is, upon fleshy descent or circumcision (including all ritual and natural merit-works,) for justification. As all their regeneration is of the flesh, so they are children of the flesh. So our Lord says, John 3:6, That which is born of the flesh is flesh; (see note;) that is, is carnal. But those here specified by Paul are not the unregenerate simply, but the falsely regenerate through fleshly lineage, and what he calls (Hebrews 9:10) fleshly ordinances. But the conclusive proof-text is, Galatians 4:29, “But as then he that was born after the flesh persecuted him that was born of the Spirit, even so it is now.” The now demonstrates that the Judaizers of Paul’s own day are by him held to be children of the flesh after the type of Ishmael of old, because they trusted in fleshly lineage and merit-works for justification. And so in Romans 4:1-12, (where see note,) justification by works and according to the flesh is the same thing.

On the contrary, the true believers “are the circumcision, and have no confidence in the flesh.” (Philippians 3:3.) That the phrase children of the flesh here has this meaning is made sure by its opposed phrases children of God, children of the promise. Forced by his creed, Professor Stuart would define children of God, “such children as God, according to the special promise to Abraham, would raise up for his posterity”! It is perfectly inadmissible, without some forcible reason, to make the phrase mean anything else than its ordinary sense in the New Testament, regenerate children of God, that is, by faith. That by children of the promise he means the regenerate by faith appears from Galatians 3:29: “If ye be Christ’s, then are ye Abraham’s seed, and heirs according to the promise.” And again, (Galatians 4:28,) “We, brethren, as Isaac was, are the children of the promise.” And the whole passage (Galatians 4:21-31) affirms just this: The faith by which Abraham and Sarah so believed in God’s promise that Isaac was generated a child of the promise is typical of that faith by which every true believer is regenerated, and so becomes also an heir of the promise. (See notes on Romans 4:17-22.) Isaac was heir of the external prerogatives of the great Abrahamic-Messianic line by physical birth, and of its internal blessings by faith; true believers, now that the external prerogatives are abolished, are, with Isaac and “in Isaac,” the “seed called” to the internal blessings by like faith. And it is this meaning that the inspired apostle reads into the words, “In Isaac shall thy seed be called.”