What greater works did Jesus refer to in John 14:12?

In John 14:12, Jesus promises that His followers will perform greater works because He is going to the Father. This statement implies that the scope of the work of the Gospel would expand significantly through the apostles and subsequent believers. As the Church grew, empowered by the Holy Spirit, the message of Christ spread throughout the world, hitting far more audiences than Jesus' ministry did during His earthly life. The 'greater works' encompass the spiritual transformation and salvation of souls through faith in Jesus—a work that would result in countless lives turning to Him for eternal life, as the Gospel is proclaimed to all nations.