but to those that are called, both Jews and Greeks, Christ God's power and God's wisdom.

but to those who have received the Call, whether Jews or Greeks, Christ the power of God and the wisdom of God.

But to those of God's selection, Jews and Greeks, Christ is the power and the wisdom of God.

But to those who have been called, Jews as well as Greeks, the Christ is the virtue of God and the wisdom of God.

Both Greeks and Jews He shows by this contrast, that the fact that Christ was so unfavorably received, was not owing to any fault on his part, nor to the natural disposition of mankind generally, but arose from the depravity of those who were not enlightened by God, inasmuch as the elect of God, whether Jews or Gentiles, are not hindered by any stumblingblock from coming to Christ, that they may find in him a sure salvation. He contrasts power with the stumblingblock, that was occasioned by abasement, and wisdom he contrasts with folly The sum, then, is this: -- "I am aware that nothing except signs has effect upon the obstinacy of the Jews, and that nothing soothes down the haughtiness of the Greeks, except an empty show of wisdom. We ought, however, to make no account of this; because, however our Christ in connection with the abasement of his cross is a stumblingblock to the Jews, and is derided by the Greeks, he is, notwithstanding, to all the elect, of whatever nation they may be, at once the power of God unto salvation for surmounting these stumblingblocks, and the wisdom of God for throwing off that mask." [1]

Footnotes

1 - "Pour oster et faire esvanoir ceste vaine apparence, et masque de sagesse;" -- "For taking away and causing to vanish, that empty show and mask of wisdom."

But unto them which are called - To all true Christians. See the note at 1-Corinthians 1:9.
Both Jews and Greeks - Whether originally of Jewish or Gentile extraction, they have here a common, similar view of the crucified Saviour.
Christ the power of God - Christ appears to them as the power of God; or it is through him that the power of salvation is communicated to them. See the note at 1-Corinthians 1:18.
And the wisdom of God - The way in which God evinces his wisdom in the salvation of people. They see the plan to be wise. They see that it is adapted to the end. They see it to be suited to procure pardon, and sanctification, and eternal life. It is God's wise plan for the salvation of people; and it is seen by those who are Christians, to be adapted to this end. They see that there is a beauty in his character; an excellency in his doctrines; and an efficacy in his atonement, to secure their salvation. - We may remark on this verse:
(1) That when people become Christians, their hearts are changed. The views of Christians are here represented as diametrically opposite to those of other people. To one class, Christ is a stumbling-block; to others, folly; to Christians he is full of beauty. But those views of the Christian, can be obtained only by a change of heart. And the change from regarding an object or being as foolishness to regarding it as full of beauty, must be a radical and a mighty change.
(2) all Christians have similar views of the Saviour. It matters not whether they were Jew or Greek; it matters not whether they were born in a northern or southern clime - "whether an Indian or an African sun has burned upon them;" whether they speak the same or different languages; whether they were born amidst the same or different denominations of Christians; whether in the same or different countries; or whether they are people in the same or different Christian communities, they have the same views of the Saviour. They see him to be the power and the wisdom of God. They are united in him, and therefore united to each other; and should regard themselves as belonging to the same family, and as bound to the same eternal home.
(3) there is real efficacy in the plan of salvation. It is a scheme of power. It is adapted to the end, and is admirably suited to accomplish the great effects which God designs to accomplish. It is not a scheme intended to show its own imbecility, and the need of another and an independent agent to accomplish the work. All the effects which the Holy Spirit produces on the soul, are such, and only such, as the truth of the gospel is adapted to produce in the mind. The gospel is God's plan of putting forth power to save people. It seizes upon great elements in human nature; and is adapted to enlist them in the service of God. It is just suited to man as a being capable of reasoning and susceptible of emotion; as a being who maybe influenced by hope and fear; who may be excited and impelled to duty by conscience, and who may be roused from a state of lethargy and sin by the prospect of eternal life, and the apprehension of eternal death. "As such" it should always be preached - as a system "wise," and "adapted" to the great end in view, as a system most powerful and "mighty to the pulling down of strong holds."

But unto them which are called - Τοις κλητοις. Those, both of Jews and Greeks, who were by the preaching of the Gospel called or invited to the marriage feast, and have accordingly believed in Christ Jesus; they prove this doctrine to be divinely powerful, to enlighten and convert the soul, and to be a proof of God's infinite wisdom, which has found out such an effectual way to glorify both his justice and mercy, and save, to the uttermost, all that come to him through Christ Jesus. The called, or invited, κλητοι, is a title of genuine Christians, and is frequently used in the New Testament. Ἁγιοι, saints, is used in the same sense.

But unto them which are called,.... Effectually, by the grace of God, not merely externally, but internally; these have other sentiments of Christ, and the doctrine of salvation by him; for being called out of darkness, and savingly illuminated by the Spirit of God, they see wisdom, beauty, glory, excellency, and suitableness in Christ, and in his Gospel; and having felt the power of it upon their souls, with them,
both Jews and Greeks, of whatsoever nation they be, and whatsoever their prejudices have been, Christ, to them is,
the power of God, and the wisdom of God: he is "the power of God"; this is opposed to the Jews who stumbled at his weakness, his sufferings and death, even the death of the cross; and is to be understood of him, not as God, in which sense he is Mighty, yea, the Almighty, and which appears by his works of creation and providence; but as Mediator, and of him in his low and mean estate, and even when he was crucified through weakness; in respect to that very thing in which he was weakness, and so stumbling, to others, he is to them that are called the power of God; as is clear by his bearing all the sins of his people in his own body, on the tree, the cross whereon he was crucified, and all the punishment due thereunto; and yet he failed not, nor was he discouraged, nor did he give out, till he had satisfied law and justice perfectly, and made a full end of sin, and an entire reconciliation for iniquity; as also by destroying, by his death, the devil, who had the power of death, and spoiling all his principalities and powers, triumphing over them on his cross; by redeeming his people from all their sins, and the curse of the law, and from him that was stronger than they; by abolishing death, and at last raising himself from the dead; all which show him, even when and "though" crucified, to be the power of God, or to be possessed of Almighty power; for these are things which a mere creature could never have done: and he is "the wisdom of God", also, in the account of these persons; and which likewise is to be understood, it being opposed to the opinions the Greeks had of him, not of him as the essential wisdom of God, as he is the wise Creator and Governor of the universe; but of him as Mediator, and in respect to that for which the Greeks accounted him foolishness: for in redemption and salvation by a crucified Christ, God hath abounded towards us in all wisdom and prudence: there is in this article a high display of the wisdom of God; for hereby justice was satisfied in that nature which sinned, and Satan destroyed in that nature which he himself had been the ruin of; hereby sin was condemned, and yet the sinner saved; pardon and justification came to be in a way of grace, and yet of strict justice; all the divine perfections harmonize, and are glorified, and God has hereby executed his wise designs and counsels of old; yea, even the wisdom of God is seen in Christ's dying the death of the cross, whereby he appeared to be made a curse for us, that he might redeem us from the curse of the law, and that the blessing of Abraham might come upon us.

called--(compare 1-Corinthians 1:26). The same class as the "us which are (being) saved" (1-Corinthians 1:18); the elect, who have obeyed the call; called effectually (Romans 8:28, Romans 8:30).
Christ--"Crucified" is not here added, because when the offense of the cross is overcome, "Christ" is received in all His relations, not only in His cross, but in His life and His future kingdom.
power--so meeting all the reasonable requirements of the Jews who sought "a sign." The cross (the death of a slave), which to the Jews (looking for a temporal Messiah) was a "stumbling-block," is really "the power of God" to the salvation of all who believe.
wisdom of God--so really exhibiting, and in the highest degree (if they would but see it), that which the Greeks sought after--wisdom (Colossians 2:3).

But to them that are called - And obey the heavenly calling. Christ - With his cross, his death, his life, his kingdom. And they experience, first, that he is the power, then, that he is the wisdom, of God.