The interior of the church is more than a convenient meeting place; it is designed as an expression of Christian life, imagery dating from the earliest days of the Church: "You form a building which rises on the foundation of the apostles and prophets, with Christ Jesus himself as the capstone." (Ephesians 2) As in the imagery from Ephesians, Christ is the capstone, dominating the interior of St. Paul's Church in the bas relief above the altar. In the nave the row of pillars not only holds up the roof but represents the "foundation of the apostles and prophets." The effect is to focus attention on the sanctuary.

The sanctuary is the center of public worship in the liturgy of the Mass. It contains the altar in the center, the lectern to the left, and the celebrant's chair behind the altar; to the far left is the tabernacle, where the sacrament is reserved. Christian life includes private prayer as well as public worship, and opportunity for private prayer is provided at the altar of the Blessed Sacrament, located in a small, quiet area somewhat set apart from the main church. To the side of this altar a red candle constantly burns, announcing the presence of the Eucharist and symbolizing God's continual presence in human lives, even when not consciously acknowledged. Light is a common symbol of God's presence.