Please read the passage before the homily:
Paul writes about the “mystery of devotion” as being great. He then quotes a early Christian hymn. We may ask what is the mystery of devotion. Devotion here does not mean the favorite prayers we like to say. Devotion here describes God’s devotedness to us. It is the mystery of the One who 1) was manifested in the flesh and vindicated in the spirit; (2) seen by angels and proclaimed to the Gentiles;(3) believed in throughout the world and taken up in glory.
It is described in three couplets that contras heaven and earth, and angels with humans. Somehow the mystery of devotion has both heavenly and earthly elements. Somehow the mystery of God’s devotedness is at home in the glory of heaven and among the people on earth. Somehow you and I have share in this mystery of devotion as the Church calls us into the fellowship with the truth of Christ, who is manifested in the Church and glorified in heaven.
Should Paul have been delayed in coming to Timothy, Timothy would know how to behave and teach in the Church of the living God. As we ponder the mystery of devotion, how God is devoted to us and how we can be devoted to God, we flesh out the fulness of this mystery, being at home both on earth and at home in heaven.