Acts 3:25

Ye are the children of the prophets
Of Abraham, Isaac, and Jacob, who are called prophets, ( Psalms 105:15 ) being lineally and naturally descended from them; to them belonged the prophecies of the Old Testament concerning the Messiah, and the promises of him; they were heirs of them;

and of the covenant which God made with our fathers;
so the phrase (tyrb ynb) , "children of the covenant", is used by the Jews, as peculiar to themselves; (See Gill on Romans 9:8) and so (Nyyrwa rb) , "a son of the law" ^F14, is also used by them in a like sense; the law, the covenant, and the promises, externally belonging to them:

saying unto Abraham,
( Genesis 22:18 )

and in thy seed shall all the kindreds of the earth be blessed;
meaning the Messiah, that sprung from him, and is called the son of Abraham; in whom, not only all Abraham's spiritual seed among the Jews, or the elect of God in that nation, and who were truly the children of Abraham, and of the promise, but even all the chosen of God among the Gentiles, in every nation, and of every kindred and family among them, are blessed in Christ, with all spiritual blessings; with peace, pardon, righteousness, redemption, and salvation: for this is not a form of blessing the Gentiles would use, when they blessed themselves, or others; saying, God bless thee, as he blessed Abraham's seed; for no one instance can be produced, when the Gentiles ever used such a form of blessing as this; but a prophecy of the calling of the Gentiles by the Messiah, and of their being blessed in him; see ( Galatians 3:16 ) and though this sense is departed from by modern Jews, it was what the ancient synagogue gave into ^F15.