In whom also we have obtained an inheritance, being predestinated according to the purpose of him who worketh all things after the counsel of his own will: In whom - Christ Jesus; also we - believing Jews have obtained an inheritance - what was promised to Abraham and his spiritual seed, viz. the adoption of sons, and the kingdom of heaven, signified by the privileges under the Mosaic dispensation, and the possession of the promised land, but all these privileges being forfeited by the rebellion and unbelief of the Jews, they are now about to be finally cut off, and the believing part to be re-elected, and put in possession of the blessings promised to Abraham and his spiritual seed, by faith; for without a re-election, they cannot get possession of these spiritual privileges.
Being predestinated - God having determined to bring both Jews and Gentiles to salvation, not by works, nor by any human means or schemes, but by Jesus Christ; that salvation being defined and determined before in the Divine mind, and the means by which it should be brought about all being according to his purpose, who consults not his creatures, but operates according to the counsel of his own will, that being ever wise, gracious, and good.
The original reference is still kept up here in the word προορισθεντες, being predestinated, as in the word προορισας Ephesians 1:5. And as the apostle speaks of obtaining the inheritance, he most evidently refers to that of which the promised land was the type and pledge. And as that land was assigned to the Israelites by limit and lot, both of which were appointed by God so the salvation now sent to the Gentiles was as expressly their lot or portion, as the promised land was that of the people of Israel. All this shows that the Israelites were a typical people; their land, the manner of possessing it, their civil and religious code, etc., etc., all typical; and that in, by, and through them, God had fore-determined, fore-described, and fore-ascertained a greater and more glorious people, among whom the deepest counsels of his wisdom should be manifested, and the most powerful works of his eternal mercy, grace, holiness, goodness, and truth, be fully exhibited. Thus there was nothing fortuitous in the Christian scheme; all was the result of infinite counsel and design. See on Ephesians 1:5 (note).