Red is the color of the season of Pentecost. This is the season of the church calendar when the Spirit of God comes to the followers of the way. The color red represents the flames of the fire that appeared on the heads of the disciples. It represents the Holy Spirit. This traditionally the color of high-level priests, so it also indicates holiness.
This banner is abstract and the bars can represent the flames. The three bars are a significant number as well; the number of the trinity.