Colossians 2:2

2:2 My goal is that their hearts, having been knit together in love, may be encouraged, and that they may have all the riches that assurance brings in their understanding of the knowledge of the mystery of God, namely, Christ,

Colossians 4:3

4:3 At the same time pray for us too, that God may open a door for the message so that we may proclaim the mystery of Christ, for which I am in chains.