And a stone of stumbling, and a rock of offence, even to them which stumble at the word, being disobedient: whereunto also they were appointed. A stone of stumbling - Because in him all Jews and Gentiles who believe are united; and because the latter were admitted into the Church, and called by the Gospel to enjoy the same privileges which the Jews, as the peculiar people of God, had enjoyed for two thousand years before; therefore they rejected the Christian religion, they would have no partakers with themselves in the salvation of God. This was the true cause why the Jews rejected the Gospel; and they rejected Christ because he did not come as a secular prince. In the one case he was a stone of stumbling - he was poor, and affected no worldly pomp; in the other he was a rock of offense, for his Gospel called the Gentiles to be a peculiar people whom the Jews believed to be everlastingly reprobated, and utterly incapable of any spiritual good.
Whereunto also they were appointed - Some good critics read the verse thus, carrying on the sense from the preceding: Also a stone of stumbling, and a rock of offense: The disobedient stumble against the word, (or doctrine), to which verily they were appointed. - Macknight.
Mr. Wakefield, leaving out, with the Syriac, the clause, The stone which the builders disallowed, the same is made the head of the corner, reads 1 Peter 2:7, 1 Peter 2:8 thus: To you therefore who trust thereon, this stone is honorable; but to those who are not persuaded, (απειθουσι), it is a stone to strike upon and to stumble against, at which they stumble who believe not the word; and unto this indeed they were appointed; that is, they who believe not the word were appointed to stumble and fall by it, not to disbelieve it; for the word of the Lord is either a savor of life unto life, or death unto death, to all them that hear it, according as they receive it by faith, or reject it by unbelief. The phrase τιθεναι τινα εις τι is very frequent among the purest Greek writers, and signifies to attribute any thing to another, or to speak a thing of them; of which Kypke gives several examples from Plutarch; and paraphrases the words thus: This stumbling and offense, particularly of the Jews, against Christ, the corner stone, was long ago asserted and predicted by the prophets, by Christ, and by others; compare Isaiah 8:14, Isaiah 8:15; Matthew 21:42, Matthew 21:44; Luke 2:34; and Romans 9:32, Romans 9:33. Now this interpretation of Kypke is the more likely, because it is evident that St. Peter refers to Isaiah 8:14, Isaiah 8:15 : And he shall be for a sanctuary; but for a stone of stumbling and for a rock of offense to both the houses of Israel, for a gin and for a snare to the inhabitants of Jerusalem: and many among them shall stumble, and fall, and be broken, etc. The disobedient, therefore, being appointed to stumble against the word, or being prophesied of as persons that should stumble, necessarily means, from the connection in which it stands, and from the passage in the prophet, that their stumbling, falling, and being broken, is the consequence of their disobedience or unbelief; but there is no intimation that they were appointed or decreed to disobey, that they might stumble, and fall, and be broken. They stumbled and fell through their obstinate unbelief; and thus their stumbling and falling, as well as their unbelief, were of themselves, in consequence of this they were appointed to be broken; this was God's work of judgment. This seems to be the meaning which our Lord attaches to this very prophecy, which he quotes against the chief priests and elders, Matthew 21:44. On the whole of these passages, see the notes on Matthew 21:42-44 (note).