This representation of Saints Peter and Paul together symbolizes the unity in diversity of the Church, with Peter representing its foundation and authority, and Paul representing its missionary outreach. Peter is seen as the “rock” and leader, particularly for the Jewish converts, while Paul is the Apostle to the Gentiles, spreading the message to the wider world. Their joint depiction represents the balance between the Church’s authority and its need for evangelization, as well as the reconciliation of competing views within the faith
Peter (left) holding a barque (ship)and a palm combines elements to represent Saint Peter’s role as the leader of the Church (the ship) and his eventual martyrdom (the palm of victory). The barque of Saint Peter symbolises the Catholic Church as a barque. Often, early church fathers (e.g. Tertullian) depicted the early church, like the ship of Peter and the apostles in a storm (Mark 4:34-41) buffeted storms of persecutions and temptations but the Lord restores tranquility to His Church (ship on the sea). The palm in Peter’s hand is a universal symbol of martyrdom.
Paul (right) is depicted with a sword which references his writings, where he describes the “sword of the Spirit, which is the word of God” (Ephesians 6:17). It also represents the instrument of his martyrdom (he was beheaded with a sword in Rome as a Roman citizen). In his other hand is a writing instrument which symbolizes his extensive writings that form a major part of the Christian Scriptures.