Jamieson, Fausset and Brown on 1 Corinthians 1:23

23. we--Paul and Apollos.

Christ crucified--The Greek expresses not the mere fact of His crucifixion, but the permanent character acquired by the transaction, whereby He is now a Saviour (Ga 3:1) crucified was the stone on which the Jews stumbled (Mt 21:44). The opposition of Jew and Gentile alike shows that a religion so seemingly contemptible in its origin could not have succeeded if it had not been divine.

unto the Greeks--the oldest manuscripts read "unto the Gentiles."