John Chrysostom

"Even as the testimony of Christ was confirmed in you." Under the color of praises and thanksgiving he touches them sharply. "For not by heathen philosophy," saith he, "neither by heathen discipline, but the grace of God, and by the riches, by and the knowledge, and the word given by Him, were you enabled to learn the doctrines of the truth, and to be confirmed unto the testimony of the Lord; that is, unto the Gospel. For ye had the benefit of many signs, many wonders unspeakable grace, to make you receive the Gospel. …

Homily on 1 Corinthians 2 ↗

Theophylact of Ohrid

For the word stands in place of: "through which" (δι᾿ ων). Through the word, he says, and knowledge, by which you were enriched, the "testimony," that is, the preaching about Christ, was confirmed in you; for you received this preaching not through outward wisdom, but through signs and gifts, of which you were deemed worthy.

Commentary on 1 Corinthians ↗

Thomas Aquinas

Secondly, he shows their correctness when he says: even as the testimony to Christ was confirmed among you. For the utterance of doctrine would not be correct or knowledge correct, if it disagreed with the testimony of Christ or if Christ's testimony did not have a firm hold on their hearts by faith, because, as it says in Jas (1:6): "He who wavers is like a wave of the sea that is driven and tossed by the wind." He says: in testimony to Christ, either because the prophets have spoken of Him; "To him all the prophets give testimony" …

Commentary on 1 Corinthians ↗