Based on Apostle Paul's teachings, particularly as mentioned in 1 Corinthians 2:2 in the Bible, it can be deduced that Paul argues that the only thing worth knowing is "Jesus Christ and Him crucified".
Paul emphasizes this as a cornerstone of his faith and teachings. This indicates that all wisdom and knowledge, according to Paul, is secondary and insignificant compared to the knowledge of Jesus Christ's sacrifice for humanity. According to Paul, understanding and acknowledging this is the most vital knowledge one can have. Being aware of Jesus Christ and His crucifixion is indeed of supreme importance, and that's the crux of the entire Christian faith according to Paul.
Thus, the blank in your sentence should be filled with "Jesus Christ and Him crucified".
Hence, the completed sentence is: "In contrast to Corinthian claims to have special wisdom and knowledge, Paul claims the only thing worth knowing is Jesus Christ and Him crucified".