Who was one of the twelve disciples that denied Christ three times?

The individual who denied Christ three times among the twelve disciples is Peter. This event is recorded in the Gospels, specifically in passages such as Matthew 26:69-75, where Peter, despite his earlier declarations of loyalty, disassociates himself from Jesus after the arrest of Jesus. This act of denial illustrates themes of human weakness, fear, and the complexity of faith under pressure. Peter's eventual restoration by Jesus after the resurrection, where Jesus asks him three times if he loves Him, is a significant moment of redemption and highlights the grace afforded to those who falter in their faith.

The other names mentioned—Cornelius, Paul, and Stephen—do not fit this context as they are not part of the twelve disciples. Cornelius is known as a Gentile convert to Christianity, Paul was an apostle who did not follow Jesus during His earthly ministry and became significant later for his missionary work and letters, and Stephen was one of the first deacons and is known for being the first Christian martyr.